Main Entry: co·run·dum

Pronunciation: \kə-ˈrən-dəm\

Function: noun

Etymology: Tamil kuruntam; akin to Sanskrit kuruvinda ruby

Date: 1804

: a very hard mineral that consists of aluminum oxide occurring in massive and crystalline forms, that can be synthesized, and that is used for gemstones (as ruby and sapphire) and as an abrasive