trass

• POS: Noun

CIDE DICTIONARY

trass, n. [D. tras or Gr. trass, probably fr. It. terrazzo terrace. See Terrace.].

 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.  [1913 Webster]
" The Dutch trass is made by burning and grinding a soft grayish rock found on the lower Rhine."  [1913 Webster]

OXFORD DICTIONARY

trass, n. (also tarras) a light-coloured tuff used as cement-material.

Etymology

Du. trass, earlier terras, tiras f. Rmc: cf. TERRACE