foam

Etymology

From Middle English fom, foom, from Old English fām, from Proto-West Germanic *faim, from Proto-Germanic *faimaz, from Proto-Indo-European *(s)poHy-m-os, from *(s)poH(y)- (“foam”). Cognate with German Feim (“foam”), Latin spūma (“foam”), Latin pūmex (“pumice”), Sanskrit फेन (phéna, “foam”), possibly Northern Kurdish fê (“epilepsy”).

noun

1. A substance composed of a large collection of bubbles or their solidified remains, especially:
   1. A collection of small bubbles created when the surface of a body of water is moved by tides, wind, etc.
      1798, Samuel Taylor Coleridge, The Rime of the Ancient Mariner in Lyrical Ballads, London: J. & A. Arch, p. 12, The breezes blew, the white foam flew, / The furrow follow’d free: / We were the first that ever burst / Into that silent Sea.
      And the heaven became livid with the violence of the tempest […] and the river was tormented into foam […] 1838, Edgar Allan Poe, “Siope”, in Tales of the Grotesque and Arabesque, volume 2, Philadelphia: Lea and Blanchard, published 1840, page 22
      Many [of the fish-traps] were full of fish that raised foam as they splashed about. 1969, Elechi Amadi, chapter 5, in The Great Ponds,, London: Heinemann, published 1970, page 45
   2. A collection of small bubbles formed from bodily fluids such as saliva or sweat.
      The horses were flecked with foam and their breathing was noisy. 1954, C. S. Lewis, chapter 9, in The Horse and His Boy, London: Collins, published 1974, page 118
   3. A collection of small bubbles on the surface of a liquid that is heated, fermented or carbonated.
      The last of the milk vanished in a swirl of foam and gurgling. 1938, Marjorie Kinnan Rawlings, chapter 15, in The Yearling, New York: Scribner, page 174
      It was a very good palm-wine and powerful, for in spite of the palm fruit hung across the mouth of the pot to restrain the lively liquor, white foam rose and spilled over. 1958, Chinua Achebe, Things Fall Apart, New York: Astor-Honor, published 1959, Part 1, Chapter 8, p. 74
      A slender thread of soft-drink foam traced her upper lip; 1988, Anne Tyler, Breathing Lessons, New York: Viking, Part 2, p. 167
   4. A collection of small bubbles created by mixing soap with water.
      […] she concentrated on the foam in the sink, tempering the water. 1964, Saul Bellow, Herzog, New York: Viking, page 255
   5. (firefighting) A collection of small bubbles formed by mixing an extinguishing agent with water, used to cover and extinguish fires.
2. A material formed by trapping pockets of gas in a liquid or solid.
   A foam mat can soften a hard seat.
3. (figurative, poetic) The sea.
   He is in Europe, across the foam.
   How slowly does sad Time his feathers moue? / Hast thee O fayrest Planet to thy home / Within the Westerne fome: 1595, Edmund Spenser, Epithalamion
   You must dwell beyond the foam, / But I am safe and live at home. 1885, Robert Louis Stevenson, “Foreign Children”, in A Child’s Garden of Verses, London: Longmans, Green, page 34
4. Fury.

verb

1. (intransitive) To form or emit foam.
   When the fierce North-wind with his airy forces Rears up the Baltic to a foaming fury; 1706, Isaac Watts, The Day of Judgement, lines 1–2
2. (intransitive) To spew saliva as foam; to foam at the mouth.
3. (firefighting) To coat or cover with foam.
   It used to be common practice to foam the runway prior to an emergency landing, in case a fuel-fed fire occurred.