equate

Etymology

It is inherited from Middle English equaten,^[2][3][4] borrowed from Latin aequātus (“levelled, made equal”), the past participle of aequō (“to make level, even or equal”),^{[5][6][7][2][8]} from aequus (“level, even, equal”), the source of equal.^{[3][9][7][10]} Barnhart thinks the verb may also have been formed from the earlier past participle equat (before 1420).^[6] The same Latin verb gave equation and equator.^[11][10]

Earliest recorded meaning

In early 15th-century medicine, to make the humours or elements alike in quality, to balance or harmonize them: before 1425, in the Middle English translation of Guy de Chauliac.^[2][7] Barnhart dates the verb to before 1425, with an earlier astrological use, to place a planet in its proper position.^[6][12] The OED's first record of the verb is from before 1500, for taking an average.^[5]

Semantic evolution

In Middle English the verb belonged to medicine and astrology, and soon also to calculation: Etymonline finds it used of numbers by the mid 15th century, and the OED records "to take the average of" from before 1500.^[7][5] "To make equal, to balance" is recorded from 1530 to 1755,^[5] and in astronomy, "to reduce observations to a common standard", from 1633 to 1833.^[5] In mathematics it meant to state the equality of two quantities from 1779.^[5] The everyday modern sense, "to regard or treat as equivalent", appears only in 1840 in the OED, in Gladstone,^[5] and by 1837 in Etymonline;^[7] the Oxford Dictionary of English likewise dates the current senses to the mid 19th century.^[9] The intransitive "to correspond to" is recorded in Webster's dictionary of 1934.^[5]

Timeline

• before 1425 – in medicine, to balance the humours.^[2][7]
• before 1500 – to take the average of (obsolete).^[5]
• 1530 – to make equal, to balance (obsolete by 1755).^[5]
• 1633 – in astronomy, to correct observations to a common standard (to 1833).^[5]
• 1779 – in mathematics, to state the equality of two quantities.^[5]
• 1840 – to regard or treat as equivalent.^[5] Etymonline dates this sense to 1837.^[7]
• 1934 – intransitive, to correspond or be equivalent.^[5]

Meanings

Verb

1. To regard or treat two things as the same or equivalent: Many people equate a big salary with success.^[13][5][4]
2. To make equal; to equalize.^[4][13]
3. (mathematics) To state that two quantities are equal; to put into the form of an equation.^[13][5]
4. To be equal; to correspond: The figure equates to about a week's pay.^[13][5]

Word family

• equatability
• equatable
• unequated

Related words

• equation
• equal
• equator
• equable
• adequate

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d Kurath, Hans; Kuhn, Sherman M.; Lewis, Robert E., eds. (1952–2001), Middle English Dictionary, Ann Arbor: University of Michigan Press; online edition ed. Frances McSparran et al. (2000–2018)
3. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
4. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ a b c d e f g h i j k l m n o p q Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
6. ^ a b c Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
7. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
8. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
9. ^ a b Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
10. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
11. ^ Weekley, Ernest (1921), An Etymological Dictionary of Modern English, London: John Murray
12. ^ Barnhart, Robert K., ed. (1995), The Barnhart Concise Dictionary of Etymology, New York: HarperCollins
13. ^ a b c d Collins English Dictionary (2023), Glasgow: HarperCollins