Definition of mossing:
(n) :
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 phylum Bryophyta (formerly division Musci).
(n) :
(countable) A kind or species of such plants.
(n) :
(informal) Any alga, lichen, bryophyte, or other plant of seemingly simple structure.
(v) :
(intransitive) To become covered with moss.
(v) :
(transitive) To cover (something) with moss.
(n) :
(American football, slang, countable) A spectacular catch made over 1 or multiple defenders, typically a jump ball.