bilateral

Etymology

It is formed from English bi- (“two”) + lateral (“of or at the side”),^{[2][3][4][5][6][7]} and lateral is from Latin laterālis (“belonging to the side”), from latus (“side”),^[2][3][8] a word of uncertain origin.^[2][3]

Earliest recorded meaning

Having two sides: Merriam-Webster dates the word to 1751.^[4] The OED's first record, for "of, on or arranged on two sides; placed on opposite sides of an axis", is in John Ash's dictionary of 1775, the date Etymonline also gives.^[3][2]

Semantic evolution

In law it was used from 1818 of what concerns or binds two parties, as a bilateral contract;^[3][5][9] from 1935 it was used of two countries, especially of trade and financial agreements between them, in contrast to multilateral ones.^[3][5] In anatomy and medicine it describes what affects both the right and the left side of the body or both of a pair of organs,^[4] and in biology bilateral symmetry is symmetry about a plane.^[5] In British education after 1947 a bilateral secondary school offered two of the three types of course, grammar, modern and technical.^[3] Sociologists use it for descent traced through both parents.^[10]

Timeline

• 1751 – having two sides.^[4]
• 1775 – of or arranged on two sides (Ash's dictionary).^[3][2]
• 1818 – law, concerning or binding two parties.^[3]
• 1935 – concerning two countries, especially in trade.^[3]
• 1947 – education, of a school offering two types of secondary course.^[3]

Modern meaning

Adjective

1. Having or involving two sides.
2. Involving, affecting or binding two parties, especially two countries: bilateral talks between the two governments.
3. (anatomy) Affecting both the right and left sides of the body, or both of a pair of organs.
4. Having bilateral symmetry, with matching halves on either side of an axis.
5. (sociology) Tracing descent through both the mother's and the father's lineage.
6. (education) Of a secondary school, offering two of the three types of course.

Noun

1. A meeting or talks between two people or groups.

Word family

• bilateralism
• bilaterally
• bilateralness

Related words

• lateral
• unilateral
• multilateral

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ a b c d e f g h i j k Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
4. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ a b c d Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
6. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
7. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
8. ^ The Chambers Dictionary (2014), 13th ed., Edinburgh: Chambers
9. ^ Garner, Bryan A., ed. (2004), Black's Law Dictionary, 8th ed., St. Paul, Minn.: Thomson West
10. ^ Collins English Dictionary (2023), Glasgow: HarperCollins