foam foam /ˈfoʊm/

noun

1. () A mass of small bubbles formed in or on a liquid  ( froth , foam )
   a mass of small bubbles formed in or on a liquid
    The beer had a thick head of foam
   the beer had a thick head of foam
   
   
2. () A lightweight material in cellular form; made by introducing gas bubbles during manufacture  ( foam )
   a lightweight material in cellular form; made by introducing gas bubbles during manufacture
   

verb

1. () Become bubbly, frothy or foaming  ( effervesce , fizz , form bubbles , foam , froth , sparkle )
   become bubbly, frothy or foaming
    The boiling soup was frothing
   The boiling soup was frothing
    The river was foaming
   The river was foaming
    Sparkling water
   sparkling water