Perpendicular

Perpendicular (pronounced pur-puhn-dik-yuh-ler)

(1) Vertical; straight up and down; upright; normal at right angles to a horizontal plane.

(2) In geometry, meeting a given line or surface at right angles.

(3) Maintaining a standing or upright position; standing up; exactly upright; extending in a straight line toward the centre of the earth, etc.

(4) In architecture, noting or pertaining to the last style of English Gothic, prevailing from the late fourteenth to the early sixteenth centuries and characterized by by stiff, rectilinear lines and the use of predominantly vertical tracery, an overall linear, shallow effect, depressed or four-centre arch, fan-tracery vaulting, panelled walls and fine intricate stonework (should be used with an initial capital letter so it’s not confused with being a purely geometric reference).

(5) In rock-climbing, a sharply pitched or precipitously steep mountain face.

(6) Moral virtue or uprightness; rectitude (largely obsolete).

(7) In Admiralty jargon, either of two lines perpendicular to the keel line, base line, or designed water line of a vessel.

(8) In surveying, a device such as a plumb line that is used in making or marking a perpendicular line.

(9) In historic slang, a meal taken while standing at the bar of a tavern (obsolete).

1350–1400: From the Middle French perpendiculaire, from the Old French perpendiculer, from the Latin perpendiculāris (vertical, as a plumb line), the construct being perpendicul(um) (plumb line), from pendēre (to weigh hang) and perpendere (carefully to balance (the construct of which was per- (thoroughly) + pendēre (to hang, cause to hang; to weigh)) from the primitive Indo-European root spen & pen (to draw, stretch, spin) + āris.  The suffix -aris was a form of -ālis with dissimilation of -l- to -r- after roots containing an l (the alternative forms were -ālis, -ēlis, -īlis & -ūlis); it was used to form adjectives, usually from noun, indicating a relationship or a "pertaining to”.  The French borrowing replaced the Middle English perpendiculer(e) and is the source of the modern pendant.  The noun from existed from the 1570s (the earlier noun was the circa 1400 perpendicle) and in astronomy, navigation and related matters, it was in the late fifteenth century the sense of a line "lying at right angles to the horizon" developed from an earlier adverb referring to "at right angles to the horizon.

The noun perpensity (consideration, a pondering, careful attention) appears first to have been used in the early eighteenth century, the construct being the Latin perpens- (past-participle stem of perpendere (carefully to balance) and has since the late nineteenth century been listed either as archaic or obsolete.  Perpendicular is a noun and adjective, perpendicularness & perpendicularity are nouns and perpendicularly is an adverb; the noun plural is perpendiculars.  Although perpendicular describes what nominally is an absolute value, most dictionaries acknowledge the comparative more as perpendicular & the superlative as most perpendicular, reflecting the use of the word to describe also the “quality of that which tends towards”, hence the existence in geometry, mathematics, architecture & engineering of the presumably helpful adjective quasiperpendicular to refer to the mysterious “partially perpendicular”.

In audio engineering, a perpendicular recording is the technique of creating magnetic data storage using vertical as opposed to longitudinal magnetization.  The synonym used in a technical context is orthogonal (independent of or irrelevant to each other).  To most, the idea of the perpendicular is simple but it’s been borrowed to describe some complex concepts such as the perpendicular universe (though these perhaps by definition seem usually to be referred to in the plural as perpendicular universes) which exists to distinguish it from a parallel universe (which must in some way be different).  The perpendicular universe is thus one of the competing notions (some insist these are legitimate theories) of multiple universes which are in some way parallel (as opposed to sequential or circular) though not of necessity perpendicular.  Seems clear enough.

The Perpendicular Pronoun:  The first-person singular pronoun "I"

There is a general rule defining when to use “I” or “me” in a sentence and that is the first person singular pronoun is “I” when it’s a subject and “me” when it’s an object (the subject is the person or thing doing something, and the object is having something done to it and the often quoted example to illustrate the difference is the sentence “I love you”.  “I” is the subject of the sentence. “You” is the object of the sentence (also the object of one's affection).

Lindsay Lohan and her sister Aliana at the Melbourne Cup, 2019.

In most cases it’s easier to deconstruct the sentence than think about the rule.  To work if one should say (1) “Lindsay and I are going to the Melbourne Cup” or (2) “Lindsay and me are going to the Melbourne Cup”, deconstruction confirms (1) is correct because “I am going to the Melbourne Cup” works and “Me is going to The Melbourne Cup” does not.  That’s fine but because “me” is often wrongly used, something of a perception has evolved to suggest it must always be wrong and “I” must always be correct. However, everything depends on the sentence.  It’s correct to say “Lindsay and I both picked the winning horse” but it’s also right to say “A selfie of the winning horse with Lindsay and me”, something which can be checked by redacting either “Lindsay and” or “and me”.

Lindsay Lohan in Falling for Christmas (Netflix, 2022)

Modern English use has anyway actually banished the perpendicular pronoun from places where once it was a marker of the educated.  To say “It is I” remains supported by historic grammatical correctness but sounds now so strange (because the common form is “It’s me”) that many would it’s wrong.  Pedants fret over things like this but the world has moved on and if in answer to the question “Is that you Ali” the response came “This is she”, the antiquated correctness might discombobulate one while “It’s me” would not.