| trass | <geology> A white to gray volcanic tufa, formed of decomposed trachytic cinders; sometimes used as a cement. Hence, a coarse sort of plaster or mortar, durable in water, and used to line cisterns and other reservoirs of water. [Formerly written also tarras, tarrace, terras. The Dutch trass is made by burning and grinding a soft grayish rock found on the lower Rhine. Origin: D. Tras or Gr. Trass, probably fr. It. Terrazzo terrace. See Terrace. Source: Websters Dictionary (01 Mar 1998) |
|---|