/ mɒs; NAmE mɔːs/ noun
[ U , C ] a very small green or yellow plant without flowers that spreads over damp surfaces, rocks, trees, etc. :
moss-covered walls
—compare lichen
—see also Spanish moss
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IDIOMS
see roll verb
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WORD ORIGIN
Old English mos bog or moss , of Germanic origin; related to Dutch mos and German Moos .