English Reference
noun · verb

foam

n. · v.
US /ˈfoʊm/ UK /fˈəʊm/ foam UK spelling foamed, foaming, foams

  1. 01 B2 Upper Intermediate

    n.a mass of small bubbles that forms on the surface of a liquid.

    n.a collection of small bubbles formed on or in a liquid by agitation, fermentation, or chemical reaction.

    Simple

    The waiter poured the beer carefully to keep the foam from spilling over.

    In context

    A thick layer of white foam gathered where the waves crashed against the jagged rocks of the shoreline.

  2. 02 B2 Upper Intermediate

    n.a soft, light material used to make things like cushions, mattresses, or sponges.

    n.a lightweight, cellular solid material manufactured by trapping gas in a polymer, used for insulation or cushioning.

    Simple

    The old sofa was uncomfortable because the foam inside had become too thin.

    In context

    The package was lined with protective foam to ensure the delicate electronic components were not damaged during transit.

  3. 03 C2 Proficiency Literary

    n.a poetic way to talk about the sea or the ocean.

    n.a metonymic or poetic reference to the sea, specifically the frothy surface of waves.

    Simple

    The poet wrote about the white foam of the distant Atlantic.

    In context

    The ancient mariner watched the white foam trail behind the ship as they sailed toward the unknown horizon.

  4. 04 B2 Upper Intermediate

    v.to produce or become covered in a mass of small bubbles.

    v.to produce, emit, or become converted into foam; often used of liquids being shaken or agitated.

    Simple

    The soap began to foam as soon as she rubbed her hands together under the water.

    In context

    The chemical solution started to foam violently when the catalyst was introduced to the beaker.

  5. 05 C1 Advanced Informal

    v.to be extremely angry about something.

    v.to exhibit signs of extreme rage or fury; typically used in the idiom 'foaming at the mouth'.

    Simple

    My boss was practically foaming at the mouth when he saw the sales report.

    In context

    The protesters were foaming at the mouth with indignation after the controversial legislation was passed without a public hearing.

    Usage

    Usually appears in the phrase 'foaming at the mouth'.

    seetherage

We used spray foam and cardboard wrapped in plastic to close it.

The Conversation· 19 Aug 2026

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”).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin gem-pro *faimaz
Level B2 · Upper Intermediate
Frequency Frequent
Updated