lactation

Etymology

It is borrowed from Late Latin lactātiō (“a suckling”),^{[2][3][4][5][6]} perhaps through French lactation,^[7][8][6] which Etymonline takes as the direct source.^[9] The Latin noun is formed on the past participle stem of lactō (“to suckle”),^[9][3][8] from lac (“milk”),^{[9][7][3][10]} which Etymonline traces to Proto-Indo-European *g(a)lag- (“milk”).^[9] The Latin word for milk is also the source of lactose and of lettuce, named for its milky sap.^[10]

Earliest recorded meaning

The action of suckling an infant: 1668, in John Wilkins's Essay towards a Real Character.^[2][7][9]

Semantic evolution

Johnson (1755) defined the word as the act or time of giving suck.^[11] In the 19th century it took on the physiological sense, the secretion of milk by the mammary glands, recorded from 1857.^[2][7][9] Since 1847 it has also meant the whole period of milk production, from birth to weaning.^[2] The verb lactate is a back-formation from it, recorded from 1889.^[9][7][2]

Timeline

• 1668 – the suckling of an infant.^[2][7][9]
• 1847 – the period of milk secretion, from birth to weaning.^[2]
• 1857 – the secretion of milk by the mammary glands.^[2][7][9]

Meanings

Noun

1. The secretion of milk by the mammary glands.^[8][2][3]
2. The period during which a woman or other female mammal produces milk, from giving birth to weaning: The cow gave most milk early in her second lactation.^[8][2][3]
3. The suckling of young.^[2][3]

Word family

• lactational
• lactationally
• hyperlactation
• overlactation

Related words

• lactate
• lactic
• lactose
• lettuce

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
4. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
5. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
6. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
7. ^ a b c d e f g Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
8. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
9. ^ a b c d e f g h i Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
10. ^ a b Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
11. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.