tōfus

I. tufa or tuff; Ital. tufo, Plin. 17, 4, 3, § 29; 36, 22, 48, § 166; Vitr. 2, 7; Front. Aquaed. 122; Verg. G. 2, 214; Ov. M. 3, 160; 8, 562; Stat. S. 4, 3, 52.