'calcareous' originates from Latin, specifically the word 'calcareus', where 'calx' (genitive 'calcis') meant 'lime' or 'limestone'.

'calcareus' (Latin) passed into English through scientific/late-Latin usage; the modern English adjective 'calcareous' developed with the same form and meaning used in geology and chemistry.

Initially it meant 'of or pertaining to lime or limestone'; over time the meaning has remained largely the same, now used broadly for materials or soils containing calcium carbonate.