definition of
foam

[1] #1 foam n. [froth] a mass of small bubbles formed in or on a liquid; "the beer had a thick head of foam". wn

[2] #2 foam v. [froth, fizz, effervesce, sparkle, form bubbles] become bubbly or frothy or foaming; "The boiling soup was frothing"; "The river was foaming"; "Sparkling water". wn

[3] #3 foam n. a lightweight material in cellular form; made by introducing gas bubbles during manufacture. wn