noun
[noncount] a mass of small bubbles that are formed in or on a liquid
a substance that is like a thick liquid made of many small bubbles
a soft material that is used to make many products :foam rubber - often used before another noun
verb
foams; foamed; foaming
[no obj] :to produce foam
foam at the mouth
to produce foam from the mouth because of illness or excitement
informal :to be very angry about something