FOAM

[noun] [U] - a mass of very small bubbles formed on the surface of a liquidFurther out to sea the waves were a metre high and capped with white foam.Foam sometimes refers to a cream-like substance which is filled with bubbles of air.bath/contraceptive/shaving foamFoam is also a soft material made by adding gas bubbles to a liquid before it cools and solidifies.foam rubber/plastica foam cushion/mattress/pillow