supplementary

Etymology

It is formed from English supplement + -ary,^{[2][3][4][5][6]} and the OED compares French supplémentaire, recorded in 1790, and the earlier supplemental.^[2] Supplement is from Middle French suppleement and supplēmentum (“something added to make up a whole”),^[2][4] from suppleō (“to fill up, complete”),^[2][4] which is sub- (“up from below”) and pleō (“to fill”), from Proto-Indo-European *pele- (“to fill”).^[4]

Earliest recorded meaning

Of the nature of a supplement, added as something extra: first recorded in 1667, in R. Allestree's Causes of Decay of Christian Piety,^[2][3] and dated to the 1660s by Etymonline.^[4]

Semantic evolution

The word came later than supplemental (about 1600) and suppletory (1620s).^[4] Etymonline notes that supplemental generally means added to supply what is lacking, while supplementary has historically leaned towards something added as secondary or extra.^[4] Johnson (1755) treated the two together, as "additional; such as may supply the place of what is lost or wanting".^[7] Technical uses followed: of acts and estimates in law and parliament (1714), in mathematics of angles that together make two right angles (1809), and of state welfare payments (1864).^[2] The noun, a supplementary person or thing, is recorded from 1798, and in Parliament a supplementary is a follow-up question (1901).^[2]

Timeline

• 1667 – serving as a supplement; additional.^[2][3]
• 1714 – of acts and estimates, in law and parliament.^[2]
• 1798 – noun, a supplementary person or thing.^[2]
• 1809 – in mathematics, of two angles that together make two right angles.^[2]
• 1864 – of state welfare payments.^[2]
• 1901 – noun, in Parliament, a follow-up question.^[2]

Meanings

Adjective

1. Added as a supplement; additional, extra: The course comes with a list of supplementary reading.^[3][8][2]
2. In mathematics, of two angles or arcs, together making 180 degrees or a semicircle.^[6][2]
3. Of state payments, given in addition to other income, as in the former British supplementary benefit.^[2][6]

Noun

1. A supplementary person or thing.^[8][3][2]
2. In parliament, a question that follows up one already asked.^[2]

Word family

• nonsupplementary
• presupplementary

Related words

• supplement
• supplemental
• supply
• suppletory
• complementary

Usage notes

Collins notes that supplemental is used in the same sense chiefly in American English.^[8]

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 p q r Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
7. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
8. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins