From Middle English fome, fom, from Old English fām, 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 Kurdish fê (“epilepsy”).
foam (countable and uncountable, plural foams)
- A substance composed of a large collection of bubbles or their solidified remains.
- A substance formed by trapping pockets of gas in a liquid or solid.
- (by extension) Sea foam; (figuratively, poetic) the sea.
foam (third-person singular simple present foams, present participle foaming, simple past and past participle foamed)
- (intransitive) To form or emit foam.
- (intransitive) To spew saliva as foam, to foam at the mouth.