Definition of trass in English:

trass

(also tarras)

noun

  • [mass noun] A light-coloured variety of volcanic ash resembling pozzolana, used in making water-resistant cement.

    • ‘Although usually of lead, in Deptford the cooler was made of tarras, a cement which, like lead, did not dissolve in the acidic solution.’

Origin

Late 18th century: from Dutch tras, German Trass, based on Latin terra earth.

Pronunciation:

trass

/tras/