Meaning

• 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).

• A kind or species of such plants.

• Any alga, lichen, bryophyte, or other plant of seemingly simple structure.

  "Irish moss"

• A bog; a fen.

  "the mosses of the Scottish border"

Meaning

• To become covered with moss.

  "An oak whose boughs were mossed with age."

• To cover (something) with moss.