unilateral

Etymology

It is borrowed from New Latin ūnilaterālis,^[2][3][4][5] or formed from English uni- + lateral.^[4][6][7][8] The Latin word is built from ūnus (“one”) and latus (“side”).^[3][2] Ūnus comes from Proto-Indo-European *oi-no- (“one, unique”),^[2] while latus is of uncertain origin.^[2] Klein says the English reformer Jeremy Bentham coined it,^[3] and Etymonline that he may have been the first to use it in its legal sense.^[2] The OED compares French unilatéral, recorded from 1804, and Italian unilaterale.^[4]

Earliest recorded meaning

In botany, of a cluster of flowers, having the flowers on one side of the stalk: 1802, in R. Hall's Elements of Botany.^[4] The sense "done by one side only" is also recorded in 1802, in a letter of W. Windham.^[4] Etymonline and Merriam-Webster also date the word to 1802.^[2][8]

Semantic evolution

The word had two lines of meaning from the start, the physical "on one side only" and "done by one party only".^[4] In law it was used from 1826 of a contract or obligation that binds only one party.^[4] Medicine used it from 1843 for something affecting one side of an organ, and since 1877 one side of the body.^[4] The figurative sense "one-sided", dealing with only one side of a subject, is recorded from 1830.^[4] Unilateral disarmament, disarming by one state whatever others do, is recorded from 1914 by Etymonline and since 1929 by the OED, later often of nuclear weapons.^[2][4] Of parking, restricted to one side of the street, it dates from 1945.^[4][2]

Timeline

• 1802 – in botany, with flowers on one side only; done by one side only.^[4][2][8]
• 1826 – in law, binding one party only.^[4]
• 1830 – one-sided, dealing with one side of a subject.^[4]
• 1843 – affecting one side of an organ.^[4]
• 1914 – unilateral disarmament.^[2]
• 1945 – of parking, on one side of the street only.^[4][2]

Meanings

Adjective

1. Done or decided by only one of two or more people, groups or countries, without the agreement of the others: a unilateral ceasefire.^[8][9][4]
2. (law) Of a contract or obligation, binding only one party.^[8][9][4]
3. Of, on or affecting only one side, especially one side of the body: unilateral hearing loss.^[9][4][8]
4. (botany) Having parts arranged on or turned to one side of an axis.^[9][4][7]
5. Tracing descent through ancestors of one sex only.^[9]
6. Dealing with only one side of a subject; one-sided.^[8][4]

Word family

• unilaterally
• unilaterality
• unilateralism

Related words

• bilateral
• multilateral
• lateral
• unit
• unique

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ a b c Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
4. ^ a b c d e f g h i j k l m n o p q r s t u Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
5. ^ Partridge, Eric (1966), Origins: A Short Etymological Dictionary of Modern English, 4th ed., London: Routledge & Kegan Paul
6. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
7. ^ a b Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
8. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
9. ^ a b c d e Collins English Dictionary (2023), Glasgow: HarperCollins