A mass of small bubbles formed on or in liquid, typically by agitation or fermentation. The waves crashed against the shore, leaving a trail of white foam on the sand.
A lightweight form of rubber or plastic made by solidifying liquid foam, used for insulation or to make items such as furniture. The mattress is made of memory foam, which conforms to the shape of your body.
A frothy substance, especially one used in cleaning or cosmetic products. She applied a generous amount of shaving foam before using the razor.