means A small, soft, non-flowering plant that grows in dense green carpets on damp ground, rocks, and tree bark.

from From Old English 'mos,' meaning bog or marsh as much as the plant itself — the early sense was the wet ground where the stuff thrived, not just the green velvet on top. It has deep Germanic roots, a cousin of Old Norse 'mosi' and German 'Moos,' and is possibly related distantly to Latin 'muscus' (moss). The blurring of 'wet place' and 'plant of the wet place' lingers in English place-names ending in -moss, marking old peat bogs across the north.