n. & v.
n. 1 a mass of small bubbles formed on or in liquid by agitation, fermentation, etc. 2 a froth of saliva or sweat. 3 a substance resembling these, e.g. rubber or plastic in a cellular mass.
v.intr. 1 emit foam; froth. 2 run with foam. 3 (of a vessel) be filled and overflow with foam. foam at the mouth be very angry. foamless adj. foamy adj. (foamier, foamiest ).
[ OE fam f. WG ]