• Webster's Revised Unabridged Dictionary
    • n Trass (Geol) 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.☞ The Dutch trass is made by burning and grinding a soft grayish rock found on the lower Rhine.
    • ***
Century Dictionary and Cyclopedia
    • n trass An earthy or more or less compact rock, made up in large part of firmly comminuted pumice or other volcanic material. It is of a pale-yellow or grayish color, and rough to the feel. Trass closely resembles pozzuolana, and like that is extensively used for hydraulic cement, especially by the Dutch engineers. It is largely quarried for that purpose along the Rhine, between Mainz and Cologne. Also terras. See tuff.
    • ***
Chambers's Twentieth Century Dictionary
    • n Trass tras a volcanic earth used as a hydraulic cement.
    • ***


Webster's Revised Unabridged Dictionary
D. tras, or Gr. trass, probably fr. It. terrazzo, terrace. See Terrace
Chambers's Twentieth Century Dictionary
Dut. tras.


In literature:

The phlegmatic Trass boy, with his moon face only expressing peasant parentage, calmly spoke some undeniably true words concerning destiny.
"Whilomville Stories" by Stephen Crane