• (a.) Having the surface rough and crumbling; as, many lichens are tartareous. • (a.) Consisting of tartar; of the nature of tartar. • (a.) Of or pertaining to Tartarus; hellish.
Tar·ta're·ous adjective [ Confer 1st Tartarous .] 1. Consisting of tartar; of the nature of tartar. 2. (Botany) Having the surface rough and crumbling; as, many lichens are tartareous .