mortar (n.2)

"bowl for pounding, vessel in which substances are beaten to powder by means of a pestle," c. 1200, from Old French mortier "bowl; builder's mortar" and directly from Latin mortarium "bowl for mixing or pounding," also used of the material prepared in it, a word of unknown origin as it is impossible now to determine which sense was original. Watkins says probably from PIE root *mer- "to rub away, harm;" de Vaan finds this plausible. Late Old English had mortere, from the same Latin source, which might also be a source of the modern word. German Mörser also is from Latin.