noun

1. the whitish mass of bubbles formed on or in liquids by agitation, fermentation, etc.
2. something like foam, as the heavy sweat of horses, or frothy saliva
3. Old Poet. the sea
4. a kind of colloid in which a gas is suspended in a liquid or solid matter, having a texture ranging from soft and liquid, as whipped cream, to firm and elastic, as foam rubber

Etymology: ME fom < OE fam, akin to Ger feim, scum < IE base *(s)poimno-, foam > Sans phḗna-, L spuma

intransitive verb

transitive verb