foam

Etymology

It is inherited from Middle English fom, fome,^[2][3][4] inherited from Old English fām (“foam, froth; the sea”),^[2][5][6] inherited from Proto-Germanic *faimaz;^[7][8] Hoad and Etymonline give the West Germanic form Proto-West Germanic *faimo-.^[6][2] It is related to Old High German feim (modern Feim)^[5][9] and to Norwegian feim (“thin layer, coating”).^[7][4] Outside Germanic it has cognates in Sanskrit फेन (phéna, “foam”), Old Church Slavonic пѣна (pěna, “foam”), Lithuanian spáinė (“streak of foam”), Old Prussian spoayno and Latin spūma (“foam”) and pūmex (“pumice”),^[2][8][9] the sources of spume and pumice.^[10] Etymonline reconstructs Proto-Indo-European *(s)poi-mo- (“foam, froth”),^[2] and Barnhart *(s)phoim- beside *(s)phoin-;^[8] Kroonen explains the forms with -m- and -n- as one old stem with both suffixes.^[7][5] The verb continues fǣman, but in the 14th century that verb was replaced by a new one formed on the noun, without its umlaut.^[5][11]

Earliest recorded meaning

A mass of tiny bubbles formed in a liquid, in an Old English glossary, and the foaming saliva of a sick person or the froth of sweat on a horse, in the Old English Bede.^[5] The Old English word also meant the sea itself.^[2][5]

Semantic evolution

Barnhart finds the Middle English noun first in the sense "something unstable" (about 1275), then for saliva (1290) and for froth on the shore (before 1393).^[8] The poetic sense "the sea" lasted from Old English into later verse.^[5] In the verb, frothing at the mouth served from the start as an image of rage;^[5] Barnhart finds a northern famen "to flow over" about 1375 and fomen "to froth at the mouth" in the Wycliffe Bible.^[8] Johnson (1755) defined the noun as the white substance that agitation or fermentation gathers on top of liquids.^[12] The 20th century added the foam used in fire-fighting (1907) and foam rubber and foam plastic (1937).^[5][2] In American slang, at first among Black speakers, foam meant beer from 1908.^[13]

Timeline

• Old English – froth, foaming saliva, and (poetic) the sea.^[5]
• Old English – verb, to emit foam.^[5]
• about 1275 – fom, “something unstable”.^[8]
• 1398 – of a liquid, to froth.^[5]
• 1726 – to fill a cup with foaming liquor.^[5]
• 1907 – fire-fighting foam.^[5]
• 1908 – (US slang) beer.^[13]
• 1937 – foam rubber and foam plastic.^[5][2]

Modern meaning

Noun

1. A mass of small bubbles formed on or in a liquid by shaking, fermentation or effervescence; froth.
2. Frothy saliva from the mouth, or the frothy sweat of a horse.
3. A light, spongy solid made by trapping gas bubbles in rubber or plastic, used for packing, padding and insulation: a foam mattress.
4. A thick frothy substance used to put out fires, or sold for shaving or styling hair.
5. (poetic) The sea.

Verb

1. To form or give off foam; to froth.
2. To be very angry, especially in foam at the mouth.
3. To make something into foam, or to fill it with foam.

Word family

• foamless
• foamable
• foamer
• foamingly
• foamlike
• defoam
• foamflower
• foamy

Related words

• spume
• pumice

Usage notes

In Scots, fame or feam could mean a great heat or a fit of rage ("in a mighty feim"), and in East Anglia the word was also used for smoke or scum.^[14]

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
4. ^ a b 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 Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
6. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
7. ^ a b c Kroonen, Guus (2013), Etymological Dictionary of Proto-Germanic, Leiden Indo-European Etymological Dictionary Series 11, Leiden / Boston: Brill
8. ^ a b c d e f Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
9. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
10. ^ Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
11. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
12. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.
13. ^ a b Green, Jonathon (2010), Green's Dictionary of Slang, London: Chambers; digital ed. 2016–, https://greensdictofslang.com
14. ^ Wright, Joseph, ed. (1898–1905), The English Dialect Dictionary, 6 vols., Oxford: Henry Frowde; via EDD Online 4.0, University of Innsbruck (CC BY 4.0)