[ bahy-lat-er-uh l ]
/ baɪˈlæt ər əl /


pertaining to, involving, or affecting two or both sides, factions, parties, or the like: a bilateral agreement; bilateral sponsorship.
located on opposite sides of an axis; two-sided, especially when of equal size, value, etc.
Biology. pertaining to the right and left sides of a structure, plane, etc.
Chiefly Law. (of a contract) binding the parties to reciprocal obligations.
through both parents equally: bilateral affiliation.Compare unilateral(def 7).


Informal. a bilateral agreement, especially regarding international trade.

Origin of bilateral

First recorded in 1765–75; bi-1 + lateral

Related forms

bi·lat·er·al·ism, bi·lat·er·al·ness, nounbi·lat·er·al·ly, adverb Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for bilateral

British Dictionary definitions for bilateral


/ (baɪˈlætərəl) /


Derived Forms

bilaterally, adverb
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for bilateral


[ bī-lătər-əl ]


Having or formed of two sides; two-sided.
Having or marked by bilateral symmetry.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.