a. [f. BI- pref.2 1, 6 + LATERAL, f. L. later- (nom. latus) side.] Of, pertaining to, affecting, or arranged upon two sides; disposed on opposite sides of an axis.
1775. Ash, Bilateral, Having two sides, both by the father and mother’s side.
1854. H. Miller, Footpr. Creat., ix. (1874), 162. That bilateral symmetry of the skeleton.
b. Law. Pertaining to or affecting two parties.
1818. Colebrooke, Obligations, I. 16. Contracts are either unilateral or bilateral.
1850. Alison, Hist. Europe, V. xxvii. § 99. 78. Bound to perform the other side of the bilateral engagement.
Hence Bilaterally adv., in a bilateral manner, on both sides. Bilateralism, Bilaterality, Bilateralness, bilateral condition, arrangement on opposite sides of an axis.
1849. Murchison, Siluria, App. D. 540. Growing bilaterally and branching regularly.
1875. Poste, Gaius, I. (ed. 2), Introd. 8. A judgement may be bilaterally penal … may both impoverish the defendant and enrich the plaintiff.
1852. Todd, Cycl. Anat. & Phys., IV. 850/1. The idea of bilateralism is by no means included in our definition of symmetry.
1880. Nature, XXI. 262. The phenomenon of bilateralness in the prothallia of ferns.
