From Middle English mos, from Old English mos (“bog, marsh, moss”), from Proto-Germanic *musą (“marsh, moss”), from Proto-Indo-European *mūs-, *meus- (“moss”). Cognate with Old High German mos (German Moos, “moss”), Icelandic mosi, Danish mos, Swedish mossa, Latin muscus (“moss”).
- Any of various small, green, seedless plants growing on the ground or on the surfaces of trees, stones, etc.; now specifically, a plant of the division Bryophyta (formerly Musci).
- (countable) A kind or species of such plants.
- (informal) Any alga, lichen, bryophyte, or other plant of seemingly simple structure.
- Spanish moss; Irish moss; club moss.
- (now chiefly UK regional) A bog; a fen.
- the mosses of the Scottish border
- The plural form mosses is used when more than one kind of moss is meant. The singular moss is used referring to a collection of moss plants of the same kind.
- (Bryophyta): bryophyte
- (intransitive) To become covered with moss.
- An oak whose boughs were mossed with age.
- (transitive) To cover (something) with moss.