1802, from Modern Latin unilateralis, from unum, neuter of unus "one" (from PIE root *oi-no- "one, unique") + latus (genitive lateralis) "the side, flank of humans or animals, lateral surface," a word of uncertain origin. Jeremy Bentham (1748-1832) may have been the first to use it in the legal sense of "made or entered into by one party." Related: Unilaterally. Unilateral disarmament is recorded from 1929.
It is useless for the sheep to pass resolutions in favor of vegetarianism, while the wolf remains of a different opinion. [William Ralph Inge, "Outspoken Essays," 1919]
word-forming element making nouns implying a practice, system, doctrine, etc., from French -isme or directly from Latin -isma, -ismus (source also of Italian, Spanish -ismo, Dutch, German -ismus), from Greek -ismos, noun ending signifying the practice or teaching of a thing, from the stem of verbs in -izein, a verb-forming element denoting the doing of the noun or adjective to which it is attached. For distinction of use, see -ity. The related Greek suffix -isma(t)- affects some forms.
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Definitions of unilateralism from WordNet
the doctrine that nations should conduct their foreign affairs individualistically without the advice or involvement of other nations;