From Old English 'mos' (moss, bog), from PIE *mews- (damp) — originally meant both the plant and the boggy ground.
A small, soft, green plant of the division Bryophyta, lacking true roots, growing in dense clumps or mats on moist surfaces such as rocks, trees, and soil.
From Old English 'mos' (moss; also bog, swamp, peat-bog), from Proto-Germanic *musą (moss, peat-bog), from PIE *mews- (damp, musty, boggy, moldy). The Old English word carried both meanings simultaneously — the plant and the wet terrain where it grows — and this dual sense is preserved in British place names like Solway Moss and Chat Moss (both peat bogs, not carpets of the plant). The 'bog' sense survived
The phrase 'a rolling stone gathers no moss' is recorded in English from the early sixteenth century, but the proverb existed in Latin: Erasmus included 'saxum volutum non obducitur musco' in his Adagia (1500). Interestingly, whether the proverb is a compliment or a warning depends on the culture — in some traditions, moss represents stability and wealth (so the rolling stone is foolish); in others, it represents stagnation (so the rolling stone is admired).