posterior

Etymology

It is borrowed from Latin posterior (“later, after, behind”),^[2][3][4][5] the comparative of posterus (“coming after, following, next”),^[3][6][7][8] from post (“after, behind”).^[3][6][5][9] As a noun it continues the Latin uses of the adjective as a noun: the masculine for a person who lived later or a descendant, and the neuter posterius, usually plural posteriora, for something that comes after or the hinder part of the body.^[2] Barnhart allows some influence of Middle French postérieur, but thinks direct borrowing from Latin more likely.^[4] The American Heritage Dictionary traces Latin post to the root Proto-Indo-European *apo- (“off, away”).^[6]

Earliest recorded meaning

As a noun, descendants: 1509, in J. Locher's verses in Barclay's Ship of Fools.^[2][7] The adjective, later in time or order, is first recorded in 1534, in Sir Thomas More.^[2][4][7]

Semantic evolution

The adjective first meant later in time,^[3][2] and Johnson (1755) still defined it as happening after, placed after, following.^[10] The sense situated behind, chiefly in anatomy, is recorded from 1578 in the OED,^[2] from the 1630s in Etymonline and Barnhart.^[3][4] The noun posteriors, descendants (1509–1889), and the later part (1598, in Shakespeare's Love's Labour's Lost), died out;^[2] the humorous use for the buttocks, at first plural and now usually singular, began in 1605 in Chapman's All Fools.^[2][3] Middle English already had the phrase partes posterialle (“the buttocks”).^[3] Later technical uses are in obstetrics (1886) and in statistics, where a posterior probability is one calculated after taking account of observations (1921).^[2]

Timeline

• 1509 – noun, descendants (obsolete by 1889).^[2][7]
• 1534 – later in time or order.^[2][4]
• 1578 – situated at the back, chiefly in anatomy.^[2]
• 1598 – the later part, in Shakespeare (obsolete).^[2]
• 1605 – the buttocks.^[2]
• 1628 – adverb, subsequently (obsolete by 1853).^[2]
• 1886 – obstetrics, of a posterior presentation.^[2]
• 1921 – statistics, of a probability revised after observation.^[2]

Meanings

Adjective

1. Situated at or toward the back; behind; opposed to anterior.^[11][7][2]
2. (anatomy) In human anatomy, dorsal, toward the spine.^[11][7]
3. (zoology) At or near the hind end of the body; caudal.^[11][7]
4. Coming after in time or order; subsequent.^[11][7][2]
5. (botany) Of a flower part, nearest the main stem.^[11][7]
6. (statistics) Of a probability, calculated after taking account of observations.^[2]

Noun

1. The buttocks; the rump of an animal: He landed on his posterior.^[11][7][2]
2. (archaic) posteriors: descendants.^[7][2][5]

Word family

• posteriorly
• posteriority

Related words

• post-
• posticous
• posterity
• postern
• preposterous
• a posteriori
• anterior

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 s t u v Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d e Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
5. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
6. ^ a b c The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
7. ^ a b c d e f g h i j k Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
8. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
9. ^ Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
10. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
11. ^ a b c d e f Collins English Dictionary (2023), Glasgow: HarperCollins