mush

Probably a variant of mash, or from a dialectal variant of Middle English mos (“mush, pulp, porridge”); compare Middle English appelmos (“applesauce”), from Old English mōs (“food, victuals, porridge, mush”), from Proto-West Germanic *mōs, from Proto-Germanic *mōsą (“porridge, food”), from Proto-Indo-European *meh₂d- (“wet, fat, dripping”).

Cognate with Scots moosh (“mush”), Dutch moes (“pulp, mush, porridge”), German Mus (“jam, puree, mush”), Swedish mos (“pulp, mash, mush”).

Simple contraction of mushroom.

Possibly from mush (“to drive dogs, usually pulling a sled, across snow”, verb), or mush (“(slang, rare) umbrella”, noun) (a clipping of mushroom, from the similar appearance; referring to drivers shielding passengers with umbrellas in rainy weather).

Compare French moucheter (“to cut with small cuts”).