Meaning of “sponge” - Learner’s Dictionary

sponge

noun [ C, U ] us uk /spʌndʒ/
SOFT SUBSTANCE

a soft substance full of small holes, which absorbs liquid very easily and is used for washing things

CAKE also sponge cake, uk us

a soft, light cake

(Definition of “sponge” from the Cambridge Learner’s Dictionary © Cambridge University Press)