Synonyms for Pestle (same or very similar meaning)
WordNet sense 1 (machine consisting of a heavy bar that moves vertically for pounding or crushing ores):
stampWordNet sense 2 (a heavy tool of stone or iron (usually with a flat base and a handle) that is used to grind and mix material (as grain or drugs or pigments) against a slab of stone):
Muller, pounderFrom the ODE community, based on WordNetadd/edit