SLATE, noun 1. An argillaceous stone which readily splits into plates; argillite; argillaceous shist. 2. A piece of smooth argillaceous stone, used for covering buildings. 3. A piece of smooth stone of the above species, used for writing on. SLATE, verb intransitive To cover with slate or plates of stone; as, to slate a roof. [It does not signify to tile.]
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI