Bilateral

Bilateral (pronounced bahy-lat-er-uhl)

(1) Pertaining to, involving, or affecting two or both sides, factions, parties, or the like.

(2) Located on opposite sides of an axis; two-sided, especially when of equal size, value etc.

(3) In anatomy and biology, pertaining to the right and left sides of a structure (especially in the region furthest from the median plane).

(4) In contract law, binding the parties to reciprocal obligations.

(5) In anthropology, relating to descent through both maternal and paternal lineage.

(6) In the British education system, a course combining academic and technical components.

(7) In physics, acting or placed at right angles to a line of motion or strain.

(8) In phonetics and phonology, of a consonant (especially the English clear l), pertaining to sounds generated by partially blocking the egress of the airstream with the tip of the tongue touching the alveolar ridge, leaving space on one or both sides of the occlusion for air passage.

1775: The construct is bi + lateral.  Bi-, in the sense of the word-forming element (two, having two, twice, double, doubly, twofold, once every two etc) is from the from Latin bis (twice) or bīnus (double), from the Old Latin which was cognate with the Sanskrit dvi-, the Ancient Greek di- & dis-, the Old English twi- and the German zwei- (twice, double), all from the primitive Indo-European PIE root dwo- (two), ultimate source also of the Modern English duo.  Bilateral is a noun & adjective, bilateralist, bilateralization, bilaterality & bilateralism are nouns and bilaterally is an adverb; the common noun plural is bilaterals.

It may have been in use before but was certainly nativized during the sixteenth century.  The occasionally bin- before vowels was a form which originated in French, not Latin although it’s suggested this may have been influenced by the Latin bini (twofold), the familiar example being “binary”.  In computing, it’s most associated with zero-one distinction in the sense of off-on and in chemistry, it denotes two parts or equivalents of the substance referred to although there are rules and conventions of use to avoid confusion with stuff named using the Greek prefix di- such as carbon dioxide (CO₂).  In general use, words built with bi- prefix can cause confusion.  While biennial (every two years) seems well understood, other constructs probably due to rarity remain, ambiguous: fortnightly is preferable to biweekly and using “every two months” or “twice a month” as required removes all doubt.

Lateral was first adopted as verb in the 1640s from the fourteenth century Old French lateral, directly from Latin laterālis (belonging to the side), a derivation of latus (genitive lateris) (the side, flank of humans or animals, lateral surface) of uncertain origin.  As a noun (and as “bilateral”), the precise definitional meaning "situated on either side of the median vertical longitudinal plane of the body" is from 1722.   Equilateral (all sides equal) was first used in mathematics in the 1560s, a borrowing from the Latin aequilateralis, aequi- being the suffix- meaning “equal”; contra-lateral (occurring on the opposite side) is from 1871; the adjective ipsilateral (on the same side of the body), bolting on the Latin ipse- suffix (self) dates from 1907; the use in US football to describe a lateral pass seems to have appeared in print first in 1934.  Multilateral and trilateral seem to have been seventeenth century inventions from geometry, the more familiar modern applications in international diplomacy not noted until 1802.

Conventions of use

Although one would have to be imaginative, with the Latin, there’s little limit to the compound words one could construct to describe the number of sides of a thing.  The words, being as unique as whole numbers, would also be infinite.  Whether many would be linguistically useful is doubtful; sextilateral may mislead and ūndēquadrāgintālateral (thirty nine sided) seems a complicated solution to a simple problem.

Unilateral             One-sided
Bilateral               Two-sided
Trilateral              Three-sided
Quadrilateral        Four-sided
Quintilateral         Five-sided
Sextilateral          Six-sided
Septilateral          Seven-sided
Octolateral           Eight-sided
Novilateral           Nine-sided
Decilateral           Ten-sided
Centilateral          Hundred-sided
Millelateral           Thousand-sided

The modern convention appears to be to stop at trilateral and thereafter, when describing gatherings of four or more, adopt multilateral or phrases like four-power or six-party.  Trilateral seem still manageable, adopted not only by governmental entities but also by the Trilateral Commission (founded in 1973 with members from Japan, the US, and Europe), a remarkably indiscrete right-wing think-tank.  However, in the organically pragmatic evolution of English, there it tends to stop, quadrilateral now most associated with Euclidean plane geometry (there are seven quadrilateral polygons) and used almost exclusively in that discipline and other strains of mathematics.  Outside of mathematics, it was only in the formal language of diplomacy that quadrilateral was used with any frequency.  The agreement of 15 July 1840, (negotiated between Lord Palmerston (1784-1865; variously UK prime-minister or foreign secretary on several occasions 1830-1865) and Nicholas I (1796–1855; Tsar of Russia 1825-1855) to tidy up things in the Mediterranean) between Great Britain, Russia, Austria, and Prussia was formalised as a quadrilateral treaty but the word fell from favour with quadruple alliance preferred for a later European arrangement.

Bilateral diplomacy: Lindsay Lohan meeting with Recep Tayyip Erdoğan (b 1954; prime-minister or president of the Republic of Türkiye since 2003), Ankara, 27 January 2017.

Although many of the wonks in the foreign policy establishment like to dream of a world in which everything is settled by multi-lateral discussions, in the world of the realists, it's understood the core of conflicts (which are the central dynamic of international relations) are bilateral.  Accordingly, most efforts are devoted to bilateral discussions.  In the business of predictions, it's also the relationships between two states which absorbs most of the thoughts of pundits and the long-term projections of those in the field can make interesting reading, decades later.  In 1988, Richard Nixon (1913-1994; US president 1969-1974) published 1999: Victory Without War, which with no false modesty he suggested was "...a how-to guide in foreign police for whomever was elected president in November 1988".  Given that, it's not surprising one passage has attracted recent comment: "...in the twenty-first century the Sino-US relationship will be one of the most important, and one of the most mutually beneficial, bilateral relationships in the world."  Things do appear to have worked out differently but there is a school of thought that the leadership of Xi Jinping (b 1953; general secretary of the Chinese Communist Party (CCP) and paramount leader of the People's Republic of China (PRC) since 2013) is an aberration and that his replacement is likely to be one who pursues a more cooperative foreign and economic policy because that is more likely to be in China's long-term (ie a century ahead) interest.      

Rare too is the more recent diplomatic creation, the pentalateral (five-power) treaty of which there appear to have been but two.  One was signed on 23 December 1950 between the United States, France, Cambodia, Laos, and Vietnam.  It didn’t end well.  The other pentalateral treaty was sealed in Tehran during October 2007 between Azerbaijan, Iran, Kazakhstan, Russia and Turkmenistan, the littoral countries of the Caspian Sea and was a mechanism to avoid squabbles while carving up resources.  Some assemblies are better described in other ways.  When the five permanent members of the UN Security Council (China, France, Russia, the UK & the US) plus Germany formed a now defunct standing committee to deal with issues raised by Iran’s nuclear programme, although a sextilateral, it was instead dubbed P5+1 although in Brussels, the eurocrats preferred E3+3.

Six men briefing the media about their sextilateral.  The chief negotiators of the six-party talks on North Korea’s nuclear program, Daioyutai State Guesthouse, Beijing, 23 December 2006.