supplemental

Etymology

It is formed from English supplement + -al,^{[2][3][4][5][6]} the noun supplement in the OED and Etymonline,^[2][3] the verb in the Shorter Oxford.^[7] Supplement is from Middle French suppleement and Latin supplēmentum (“something added to make up a whole”),^[2][3] from suppleō (“to fill up”).^[3][2]

Earliest recorded meaning

Serving as a supplement; additional: 1605, in Francis Bacon's Advancement of Learning.^[2][4] Dictionary.com dates the adjective to 1595–1605.^[5]

Semantic evolution

From the early 18th century the word was also used in mathematics as an equivalent of supplementary,^[2] and in American law it describes an answer, bill or pleading filed to add to or correct an earlier one.^[4][6] As a noun, a thing supplementary to another, it is recorded from 1643.^[2] The OED notes that both adjective and noun are now chiefly American,^[2][7] British English preferring supplementary.^[7]

Timeline

• 1595–1605 – the period Dictionary.com gives.^[5]
• 1605 – serving as a supplement, in Francis Bacon.^[2][4]
• 1643 – noun, a thing supplementary to another.^[2]
• 1701 – mathematics, supplementary; also the noun, a supplemental triangle (obsolete by 1723).^[2]

Meanings

Adjective

1. Serving as a supplement; added to make up for a lack or to complete something; supplementary: The course comes with supplemental reading online.^[4][2][3]
2. (law) Of a pleading, bill or answer: filed in support of an earlier one, to correct a defect in it or to add new facts.^[4][6]
3. (mathematics) Of an angle or arc: forming a supplement.^[2][7]

Noun

1. (chiefly US) A supplementary thing, such as an additional budget appropriation.^[4][2]

Word family

• supplementally

Related words

• supplement
• supplementary
• supply
• complement

Usage notes

Etymonline distinguishes the two adjectives: supplemental generally means added to supply what is wanting, while supplementary has historically leaned towards something added as secondary or extra.^[3] Supplemental is now chiefly American.^[2][7]

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n o Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d e f g Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ a b c Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ a b c Gove, Philip Babcock, ed. (1961), Webster's Third New International Dictionary of the English Language, Unabridged, Springfield, Mass.: G. & C. Merriam
7. ^ a b c d e Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press