Concerto

Concerto (pronounced kuhn-cher-toh or kawn-cher-taw (Italian))

(1) A composition for an orchestra and one or more principal instruments (ie soloists), usually in symphonic form. The classical concerto usually consisted of several movements, and often a cadenza.

(2) An alternative word for ripieno.

1519: From the Italian concertare (concert), the construct being con- + certō.  The Latin prefix con- is from the preposition cum (with) and certō is from certus (resolved, certain) +‎ -ō; the present infinitive certāre, the perfect active certāvī, the supine certātum.  Concerto grosso (literally “big concert”; plural concerti grossi) is the more familiar type of orchestral music of the Baroque era (circa 1600–1750), characterized by contrast between a small group of soloists (soli, concertino, principale) and the full orchestra (tutti, concerto grosso, ripieno). The titles of early concerti grossi often reflected their performance locales, as in concerto da chiesa (church concerto) and concerto da camera (chamber concerto, played at court), titles also applied to works not strictly concerti grossi.  Ultimately the concerto grosso flourished as secular court music.  Concerto is a noun; the noun plurals are  concertos & concerti.

The origin of the Italian word concerto is unclear although most musicologists hold it’s meant to imply a work where disputes and fights are ultimately resolved by working together although the meaning did change over the centuries as musical traditions evolved.  Concerto was first used 1519 in Rome to refer to an ensemble of voices getting together with music although the first publication with this name for works for voices and instruments is by the Venetian composer Andrea Gabrieli (circa 1532-1585) and his nephew Giovanni Gabrieli (circa 1555-1612), a collection of concerti, dated 1587. Up to the first half of the seventeenth century, the term concerti was used in Italy for vocal works accompanied by instruments, many publications appearing with this title although initially, the Italian word sinfonia (from the Latin symphōnia, from the Ancient Greek συμφωνία (sumphōnía) was also used.  It was during the Baroque era the concerto evolved into a recognizably modern form.

Deep Purple and the Royal Philharmonic Orchestra under Malcolm Arnold: Concerto for Group and Orchestra, 24 September 1969.

Although pop groups playing with orchestras is now not rare, there’s never been anything quite like Jon Lord’s (1941-2012) Concerto for Group and Orchestra, performed on 24 September 1969 at the Royal Albert Hall by Deep Purple and the Royal Philharmonic Orchestra under Malcolm Arnold (1921-2006).  The work was a true concerto in three movements: Energico, Lento and Con Fuoco; an attempt to fuse the sound of an orchestra with that of a heavy metal band.  It proved a modest commercial success and has been performed on several occasions.

Cover of the original Tetragrammaton pressing of Deep Purple's second album The Book of Taliesyn (1968).

Although something very different from what most rock bands were doing in 1969, Jon Lord's concerto really was a synthesis of some of the material two of the bands previous three albums, both of which contained threads in the tradition of the German classical music in which Lord Had been trained.  Recorded during their early quasi-psychedelic period, the title of their second album had been borrowed from The Book of Taliesin (Llyfr Taliesin in the Welsh), a fourteenth century manuscript written in Middle Welsh which contains some five dozen poems, some pre-dating the tenth century while the third owed some debt to the seventeenth & eighteenth.  The Concerto for Group and Orchestra was very much in the vein of Deep Purple's early output but what was at the time unexpected was that less than a year after the performance, the band released the album In Rock, a notable change in musical direction and one decidedly not orchestral.  Prior to In Rock, Deep Purple's output had been eclectic with no discernible thematic pattern, a mix of influences from pop, blues and psychedelia, delivered with the odd classical flourish so suddenly to produce one of the defining albums of heavy metal was unexpected in a way the Concerto was not.  For the band however, it was the performance at the Royal Albert Hall which proved the anomaly, In Rock providing the template which would sustain them, through personnel changes and the odd hiatus, well into the twenty-first century.

Cover of the original Harvest pressing of Deep Purple's fourth album: Concerto for Group and Orchestra (1969).

Lord wasn’t discouraged by the restrained enthusiasm of the music press, describing critics as “…an archaic, if necessary, appendage to the music business” and pursued variations of the concept for the rest of his life.  The most noted was Windows (1974), a collaboration with German conductor and composer Eberhard Schoener (b 1938) which included Continuo on B-A-C-H (B-A-C-B# in musical notation), a piece which built on the unfinished triple fugue that closed Johann Sebastian Bach's (1685–1750) Art of the Fugue, written in the last years of his life.  Although not included with the original release on vinyl, the band did perform some of their other material just before the concerto began including a song which would appear on In Rock.  That was Child in Time, a long and rather dramatic piece with some loud screaming which must have been quite unlike anything which some of that night's older critics might previously have enjoyed and perhaps it affected them.  Unlike pop music’s fusions with jazz, attempts to synthesize with classical traditions never attracted the same interest or approbation, the consensus seemingly that while a cobbler could create a hobnail boot for a ballerina, it was hard to imagine why.

Jelly

Jelly (pronounced jel-ee)

(1) A food preparation of a soft, elastic consistency due to the presence of gelatin, pectin etc, especially fruit juice boiled down with sugar and used as a sweet spread for bread and toast, as a filling for cakes or doughnuts etc.

(2) A preserve made from the juice of fruit boiled with sugar and used as jam (jam the preferred term in much of the English-speaking world outside North America).

(3) Any object or substance having a jelly-like consistency.

(4) A fruit-flavored gelatin dessert (in the English–speaking world but less common in North America where “jello” or “jell-o” are preferred).

(5) A “jelly shoe”, a plastic sandal or shoe, often brightly colored.

(6) To bring or come to the consistency of jelly.

(7) In theatre, film & television production, the informal term for a colored gelatin filter which can be fitted in front of a stage or studio light.

(8) A slang term for the explosive gelignite.

(9) In Caribbean (Jamaica) English, a clipping of jelly coconut.

(10) A savory substance, derived from meat, with a similar texture to the sweet dessert (the gelatinous meat product also known as aspic).

(11) In the slang of zoology, a jellyfish.

(12) In slang (underworld & pathology), blood, especially in its congealed state.

(13) In slang, an attractive young woman; one’s girlfriend (US, probably extinct).

(14) The large backside of a woman (US, now rare).

(15) In internet slang, a clipping of jealous (rare).

(16) In Indian use, a vitrified brick refuse used as metal in road construction.

(17) As “royal jelly”, a substance secreted by honey bees to aid in the development of immature or young bees, supplied in extra measure to those young destined to become queen bees.

1350–1400: From the Middle English jelyf, gelly, gelye, gelle, gelee, gele & gely (semisolid substance from animal or vegetable material, spiced and used in cooking; chopped meat or fish served in such a jelly), from the Old French gelee (frost; frozen jelly), a noun use of feminine past participle of geler (to set hard; to congeal), from the Medieval Latin gelāta (frozen), from gelu (frost), the construct being gel- (freeze) + -āta (a noun-forming suffix).  The Classical Latin verb gelō (present infinitive gelāre, perfect active gelāvī, supine gelātum) (I freeze, cause to congeal; I frighten, petrify, cause to become rigid with fright) was from gelū (frost), from the primitive Indo-European gel- (cold) and was cognate with the Ancient Greek γελανδρόν (gelandrón).  Originally quite specific, by the early fifteenth century jelly was used of any jellied or coagulated substance and by the 1700s it came to mean also "thickened juice of a fruit prepared as food" which was both a form of preserving fruit and a substance used by chefs for flavoring and decorative purposes.  The adjective jellied (past-participle from the verb jelly) emerged in the 1590s with the sense of “of the consistency of jelly” and by the late nineteenth century this had been extended to include “sweetened with jelly”.  Because of the close historical association with foods, the preferred adjectival form for other purposes is jelly-like.  As a modifier jelly has proved productive, the forms including jelly baby, jelly bag, jellybean, jelly coat, jelly doughnut, comb jelly, jelly bracelet, jelly plant & royal jelly.  Jelly is a noun & verb, jellify & jellification are nouns, jellified & jellied are verbs & adjectives and jellying is a verb; the noun plural is jellies.

Aunger "jelly bean" aluminium wheels, magazine advertisement, 1974.  A design popular in the 1970s, different manufacturers used their own brand-names but colloquially the style was known as the “jellybean”, “slotted” or “beanhole”.

The verb jell (assume the consistence of jelly) is documented since 1869 and was a coining of US English, doubtlessly as a back-formation from the noun of jelly.  The figurative use (organizations, ideas, design etc) emerged circa 1908 but with the spelling gel, a echo of the Middle English gelen (congeal) which was extinct by the late fifteenth century.  The jellyfish (also jelly-fish) was in the late eighteenth century a popular name of the medusa and similar sea-creatures, the name derived from the soft structure.  Figuratively, jellyfish was used from the 1880s for “a person of weak character” although publications from 1707 use the name for an actual vertebrate fish.  

The jelly roll.

The jellyroll (also jelly-roll) was a “cylindrical cake containing jelly or jam” which dates from 1873 and in some markets (notably Australia & New Zealand) it is sold as a “jam roll” or “Swiss Jam Roll”.  The use of jelly roll as slang for both the vagina and the act of sexual intercourse was of African-American origin circa 1914 and was mentioned several times in blues music.  The jellybean (also (rarely) jelly-bean) (small bean-shaped, multi-colored sugar candy with a firm shell and a thick gel interior) was introduced in 1905, the name obviously from the shape.  It entered US slang in the 1910s with the sense of “someone stupid; a half-wit” which was apparently the source of the slang sense of bean as “head”.  In the 1990s, jellybean was the (usually disparaging) term often applied to the depressingly similarly-shaped cars which were the product of wind-tunnels.  While aerodynamically efficient, few found the lines attractive.

1996 Ford Taurus Ghia (left) and 1996 Ford EF Falcon XR8 (right).

In 1996, Ford Australia put the US-sourced Taurus into the showrooms alongside the locally-built and well-received EF Falcon.  As well as carrying the stigma of front wheel drive (FWD), the “jellybean” styling alienated buyers, some of whom suggested the Taurus looked as if it had already been in an accident.  The Taurus was withdrawn from the Australian market after two years of dismal sales, dealers managing to clear to unsold stock only after a further year of heavy discounting.

Champagne Jelly

Champagne Jelly was served at the coronation banquet of Edward VII (1841–1910; King of the United Kingdom and Emperor of India 1901-1910) in 1902 and has since been a popular “nostalgia” dish, seen often at weddings or seasonal celebrations.

Ingredients (to serve 6)

1 bottle 750 ml bottle of Champagne
2 sachets (2½ tsp each) powdered gelatin (or 8 gelatin sheets)
2 tablespoons water (if using powdered gelatin)
115g (4oz) white sugar
Berries and/or edible flowers (optional)
Fresh mint leaves, for garnish

Instructions

(1) Place Champagne bottle in a freezer 30 minutes before beginning (this will ensure jelly will retain the bubbles

(2) In a small bowl, sprinkle the powdered gelatin, if using, over the water and let stand until softened (typically 3-5 minutes).  If using gelatin sheets, put sheets into a bowl and cover with cold water, soaking until floppy (typically 5-10 minutes).

(3) Open Champagne and pour 120ml into a small pan.  Return the Champagne to the freezer, ensuring bottle remains upright.  If this is not possible, put bottle into fridge in upright position.

(4) Add the sugar to the pan, place over a medium heat, and heat, stirring, until the sugar dissolves at which point, removed from the heat.  Liquefy the powdered gelatin by setting the bowl of softened gelatin into a larger bowl of very hot tap water (do not use boiling water).

(5) If using gelatin sheets, lift the sheets from the water, wring to release excess water, then put them into a bowl and liquefy as for the powdered gelatin.  Add the liquefied gelatin to the Champagne mixture and stir until the gelatin dissolves.

(6) Strain the mixture through a fine sieve into a bowl or pitcher, then allow it cool to room temperature.

(7) Add 480ml of chilled Champagne to the cooled gelatin mixture and stir well.  If adding berries or edible flowers, pour half of the gelatin mixture into a 600ml (1pint) mould and chill until almost set (typically 30-45 minutes).  Arrange the embellishments on top, then add the remaining gelatin mixture.

(8) If serving the jelly without embellishments, pour all the gelatin mixture into the mould.  Cover and refrigerate until fully set (at least 12 hours and preferably longer).  At this point drink remaining Champagne.  If need be, open a second bottle.

(9) To serve, fill a bowl with hot water.  Dip the bottom of the mould into the hot water for a few seconds to loosen the jelly from the mould, then place on a serving plate and garnish with mint.

Lindsay Lohan in outfit inspired by Champagne Jelly, ABC’s Good Morning America, November 2022.  The suit was from Law Roach’s (b 1978) Akris’ fall 2022 ready-to-wear collection, the ensemble including a wide-lapelled jacket, turtleneck and boot cut pants fabricated in a green, yellow, red & orange Drei Teile print in an irregular geometric pattern.  The distinctive look was paired with a similarly eclectic combination of accessories, chunky gold hoop earrings, a cross-body Anouk envelope handbag, and Giuseppe Zanotti platform heels.

Rectilinear & Curvilinear

Rectilinear (pronounced rek-tl-in-ee-er)

(1) Forming or formed by straight lines.

(2) In geometry, as rectilinear grid, a tessellation by rectangles or rectangular cuboids (also known as rectangular parallelepipeds) that are not, in general, all congruent to each other.

(3) Of, pertaining to or characterized by straight lines.

(4) In, moving in, or characterized by a movement in a straight line or lines.

(5) In architecture, as the rectilinear style, the third historical division of English Gothic architecture.

1650–1660: From the post-Classical Latin, either from rectilīneāris or from rectilīneus (the source also of rectiline) + -ar, in either case the ultimate sources being rectus (straight) + līnea (line).  Rectus was from the primitive Indo-European root reg- (move in a straight line) with derivatives meaning "to direct in a straight line".  The suffix -ar is from the Latin from -ālis with dissimilation of “l” to “r” after roots containing an “l” thus āris and used to form adjectives (usually from a noun) to convey the sense of a relationship or “of; pertaining to”.  The English adjectival suffix –ar (of, near, or pertaining to) is widely appended, usually to nouns and is not restricted to those of Latin origin (the synonymous forms including -al, -an, -ary, -ese, -ic, -id, -ish, -like, -oid, -ory, -ous & -y).  Rectilinear came to be used in the sense of “a figure bounded by straight lines" by 1728, an evolution of the earlier meaning “straight lined”.  Rectilinear & rectilineal are adjectives, rectilinearity is a noun.

Curvilinear (pronounced kur-vuh-lin-ee-er)

(1) Consisting of or bounded by curved lines.

(2) Forming or moving in a curved line.

(3) Formed or characterized by curved lines.

(4) Of lines, having bends; curved.

(4) In mathematics, a set of coordinates determined by or determining a system of three orthogonal surfaces

1690s: From the Latin, derived from curvi (a combined form of the Latin curvus (crooked, bent, curved) + līneāris, from līnea (line).  The construct of līneāris was līnea (line) + -āris (the adjectival suffix).  The Latin curvus was ultimately from the primitive Indo-European sker & ker (to bend, curve, turn) + -wós (before it became associated with perfect stems, the suffixes -wós- & -us- had a more general function, forming athematic verb participles with the meaning "having x-en").  The earlier form was curvilineal, dating from the 1650s.  Curvilinear is an adjective, curvilinearity a noun and curvilinearly an adverb.

A juxtaposition of curvilinearity and rectilinearity: Lindsay Lohan, Vanity Fair shoot, October 2010.

In engineering, as in nature, matters of rectilinearity and curvilinearity tend to be products variously of inheritance, circumstance, economics or necessity.  In design however, sometimes fashion is allowed (indeed sometimes encouraged) to prevail over function and in automotive styling, the rectilinear (known in its most extreme form as knife-edge or razor-edge design) was a motif which came and went.  In the early days when things were truly little more than starkly functional, straight lines were dominant but the industry also inherited many of the traditions of the architecture of the horse-drawn carriage and embellishments could be quite curvaceous.  Line and curve co-existed in the inter-war years and as interest grew in streamlining to improve aerodynamics, the curves actually assumed a functional purpose.  At the same time, severity of line became itself a defined style, associated with formality and wealth, structurally because the straight lines tended to exaggerate size so the bigger cars appeared larger still and perhaps psychologically because they conveyed a message of casual disregard for something like streamlining, relying instead on power.  The big, bustle-backed limousines of the pre-war years were the exemplars.

Rolls-Royce Phantom IV (1950-1956 (left)), Triumph 1800-2000 Renown (1946-1954 (centre)) & Triumph Mayflower (1949-1953 (right)).

In the post war-years, in Europe and US, designers were attracted to the new.  In Europe that meant the avant-garde while across the Atlantic it could mean anything from restrained formalism to macropterous absurdity.  In England however, there was still a hankering for the familiar and among the coachbuilders (and Rolls-Royce which had begun building its own “standard” bodies) it was “business as usual” and, barely updated, the razor-edged lines returned.  Remarkably, as a niche, the style would be produced in tiny numbers until the 1990s even as modernity overtook the land.  So clearly, on a big scale it worked for the small, exclusive market at which it was targeted, a rolling denotation of wealth and power and this was what attracted others to apply the rectilinear lines on a smaller scale, at a lower price.  The leading proponents were Standard-Triumph which in 1946 released their middle-class 1800 as a kind of shrunken (though no less angular) Rolls-Royce or Bentley.  Generally, it was judged an aesthetic success although it quickly became dated and before long, the company was emulating American cars, their shrunken versions of those rather less pleasing.  The 1800 however maintained sufficient popularity to remain in production for eight years and that encouraged the idea the motif might translate well to something even smaller.  Hence in 1949, the Triumph Mayflower, small, stubby and wholly unsuited to a style which worked only at scale; the only thing more absurd than its existence was that the company designed it with the US market in mind.  The advertising agency suggested advertising it as “the watch charm Rolls-Royce” but whether that was vetoed by threats from Rolls-Royce or watch charm makers isn’t recorded.  A failure in every market in which it was offered (conspicuously so in the US), it was replaced by an anonymous-looking blob which might have designed by someone French in an unimaginative moment or an Italian on a bad day.

1967 Cadillac Eldorado (left), 1971 Fiat 130 Coupé (centre) and 1983 Volvo 760 GLE (right).

Until the oil shocks of the 1970s forced just about everyone to take aerodynamics seriously, the rectilineal would come and go as a fashion trend.  Cadillac’s 1967 Eldorado was an outstanding example and has aged better even than its curvier companion, the Oldsmobile Toroando of a year earlier but probably the high point of the modern razor-edge was Pininfarina’s Fiat 130 Coupé, its dimensions a stylistic sweet-spot which proved as suited to the saloon and shooting brake the designer world later exhibit; regrettably, neither reached production and the coupé proved a commercial failure, albeit one much admired.  That wasn’t something often said of one of Europe’s less successful straight-edged ventures, the 1982 Volvo 700 series.  Looking something like an earnest but uninspired student at a technical college might have submitted for assessment, Volvo at the time claimed it would remain timeless over the years to come while the rounded shapes around it soon became dated.  In that they were certainly wrong, the competition becoming more curvilinear still and soon Volvos nip-and-tuck specialists were finding ways to smooth the corners, not an easy task given the shape the patient was in and something really not possible until the re-skinned 900 was released in 1990.  The 700 had, by Volvo’s standards, a short life but it’s remembered for a bon mot from another designer who mused that it “…might be a good-looking car when they take it out of the packing-case”.

1953 Jaguar C-Type (XK120-C) continuation (left), 1957 Jaguar XKSS (centre) & 1961 Jaguar E-Type (XK-E) (1961).

Curves can be mere styling devices and in the 1960s General Motors (GM) actually created a motif they called cokebottle, summoning the idea of a Coca-Cola bottle on its side, itself evocative of the female form supine.  Plans to trademark the word were abandoned when the lawyers assured everyone using a lowercase “c” and claiming it to be a portmanteau word would fool neither the Coca-Cola company nor the judge.  Sometimes though, the curves were functional, Jaguar in 1950 shaping the aluminum skin on the XK120-C (C-Type) simply to be as low and aerodynamic as possible, the curves bulging only where necessary to provide coverage for the wheels and tyres.  On the subsequent D-Type (and the road-going derivative the XKSS), the impression was that the curves had become exaggerated, bulging more sensually still.  It’s not entirely an optical illusion but the shape is wholly functional, the designers actually lowering the centre, a revised mounting of a now dry-sumped engine permitting a lower bonnet (hood) line and thus a smaller frontal area.  The wheels and tyres remained much the same height so the curvature of the skin enveloping them is so much more obvious on a body otherwise lower.  The remarkably small frontal area did the job at Le Mans; the D-Type nearly 20 mph (32 km/h) faster than Ferrari's far more powerful 375.  By the time the E-Type was released in 1961, it could actually have been done with a little less curvature but we should all be grateful it looks as it does.

1960s original (left), 2022 modern (centre) & 2022 retro (right).

Objects like refrigerators offer designers a little more scope given that a low drag coefficient hardly matters although the modern, rectilinear versions presumably optimize space efficiency, offering the highest internal volume relative to external dimensions.  That said, there’s clearly still some demand for fridges which emulate the rounded style most associated with the 1950s and 1960s, several manufacturers with a retro line and they’re available in the pastel shades of the era.

Procreate

Procreate (pronounced proh-kree-yet)

(1) To beget, engender or generate (offspring).

(2) To produce; bring into being.

1530–1540: From the Latin prōcreātus, past participle of prōcreāre (to breed), the construct being pro- + creāre (to create), prōcreāte being the second-person plural present active imperative of prōcreō (present infinitive prōcreāre, perfect active prōcreāvī, supine prōcreātum; first conjugation).  Root form was pro- +‎ creo, the pro- prefix being the combining form of prō (preposition); creo was from the Proto-Italic krēāō (to make grow) from the primitive Indo-European ḱer- (to grow; become bigger”), the same root of crēscō (I increase, rise, grow, thrive; multiply, augment).

Related forms are the nouns procreation, procreativeness & procreator, the adjectives procreant & procreative, the verbs procreated & procreating and the adjective procreative; synonyms and related terms include spawn, proliferate, originate, impregnate, parent, engender, sire, create, breed, father, generate, mother, produce, propagate, conceive, hatch, multiply, get, beget & make.

Consequences of procreation: Lindsay Lohan’s family tree.

Procreation was a theme in the Bible.  In Genesis 1:28, God tells Adam and Eve to “be fruitful and increase in number”, a point reinforced in Psalm 127:3–5 and Matthew 28:18-20.  In an early example of a social contract, in the Covenant of the Rainbow (Genesis 6:13-22 (KJV)), having told man to go forth and multiply, God granted humanity dominion over all earth and “…every beast of the earth, and upon every fowl of the air, upon all that moveth upon the earth, and upon all the fishes of the sea; into your hand are they delivered.  Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things.”

Most anxious to do the Lord’s work is Deputy Prime-Minister of Australia Barnaby Joyce (b 1967).  Having gone forth and multiplied with his wife, after pausing to condemn same-sex marriage because it threatened the sanctity of traditional marriage, he deserted his wife to go forth and multiply with his mistress.  Twice.

Theodolite

Theodolite (pronounced thee-od-l-ahyt)

(1) In surveying, a precision instrument having a telescopic sight for establishing horizontal and sometimes vertical angles; usually called a transit in US & Canada.

(2) As phototheodolite, an instrument consisting of a theodolite mounted on a camera which can take at each of several stations of known position and elevation (as determined by transit survey) a series of photographs used in terrestrial photogrammetry.

1571: From the New Latin theodolitus the origin of which is contested.  It was probably coined either from the Arabic al-idhâda (a sort of rule) or the Ancient Greek theā (a viewing) plus a second element of unknown origin which may have been invented.  The North American use of” transit” rather than theodolite is historic.  During the nineteenth century, Americans preferred the surveyor’s compass and, later, the surveyor’s transit, which were cheaper and more robust and, despite technical progress, the name stuck.

Many have attempted to trace the etymology of theodolite but no satisfactory explanation has been found.  The first use was in a book by English mathematician and surveyor Leonard Digges called Geometrical practical treatize, named Pantometria, diuided into three bookes, longimetria, planimetria, and stereometria (1571, second edition 1591).  The author didn’t mention any derivation and used the spellings “theodelitus” and “theodolitus” alternately.  Writing a few years later, another mathematician named the same instrument a “horizontall or flatte sphere”, although inconsistencies in spelling was at the time not unusual, the same author when speaking of an alidade (a sighting device or pointer for determining directions or measuring angles used in both surveying and astronomy), spelled it as “alideday” and “athelida”.

One explanation is that both theodelitus and athelidae were corruptions of the Arabic al-idhâda (a sort of rule), and both mathematicians would have been acquainted with the work of earlier Arabic mathematicians.  That’s not unconvincing for athelidae but theodelitus is more likely to have been derived from (or at least influenced by) the Ancient Greek; the second element has mystified all.  The first part of the New Latin theo-delitus might stem from the Ancient Greek θεᾶσθαι (to behold or look attentively upon) or θεῖν (to run) but the second part is puzzling though sometimes attributed to an unscholarly variation of one of the following Greek words: δῆλος (evident; clear), δολιχός (long) or δοῦλος (slave) or even an unattested Neo-Latin compound combining ὁδός (way) and λιτός (plain).  It has been also suggested that -delitus is a variation of the Latin supine deletus, in the sense of "crossed out".

From mechanical to digital

Copper & brass theodolite, Hall Brothers of London, circa 1894.

A theodolite is an optical device used to measure angles between visible points in the horizontal and vertical planes.  Historically they were used in land surveying but they’re used also in all aspects of civil engineering, meteorology and rocket telemetry.  The earliest theodolites were small mounted telescope which rotated horizontally and vertically; modern versions are sophisticated digital instruments which can track weather balloons, airplanes, and other moving objects, at distances up to 12 miles (20 km / 65,600 feet).  Nearly always used mounted on a tripod and originally mechanical-optical instruments, almost all theodolites in active use are now digital.  Theodolites, whether mechanical or digital, are instruments used to determine the relative position of points on the earth's surface by measuring the horizontal and vertical angles. Digital theodolites are more convenient and accurate as they provide the operator with readouts.  With the traditional device, it was necessary manually to read the numbers directly from a graduated circle.

The modern digital theodolite.

A digital theodolite consists of a telescope mounted on a base, a sight at the top used to align the target, vision of which is clarified by adjusting a focusing knob, an objective lens on the opposite side used to sight and magnify the target as required.  Despite the differences in construction, the parts of a digital theodolite are mostly similar to the non-digital theodolite, except for the addition of a liquid crystal display (LCD) and the operating keys for changing the settings.  In the same manner as the non-digital theodolite, leveling is performed using optical plummets or plumb bobs and the spirit or bubble level.  In use, it’s made first to stand vertically above the survey point with the help of a plumb bob or optical plummet and is then made in level to the horizon with the help of internal spirit levels.  Once the leveling process is complete, the telescope is used to focus on the target and the respective horizontal and vertical angles are displayed on the screen.