Definition of air foam in English:

air foam

Pronunciation /ˈɛː fəʊm/

noun

  • 1British A water-based foam used in firefighting.

  • 2North American Originally: a sponge-like rubber material used as padding in furniture, mattresses, and vehicle seating. Now: (a trademark for) a type of flexible synthetic padding material.

Origin

1930s; earliest use found in Nashua (Iowa) Reporter. From air + foam, apparently so called on account of its consistency.