Sponge  —n. 1 sea animal with a porous body wall and a rigid internal skeleton. 2 this skeleton or a piece of porous rubber etc. Used in bathing, cleaning, etc. 3 thing like a sponge in consistency etc., esp. A sponge cake. 4 act of sponging. —v. (-ging) 1 wipe or cleanse with a sponge. 2 (often foll. By out, away, etc.) Wipe off or efface (as) with a sponge. 3 (often foll. By up) absorb (as) with a sponge. 4 (often foll. By on, off) live as a parasite.  spongiform adj. (esp. In senses 1, 2 of the n.). [latin spongia]