corundum

/kəˈɹʌn.dəm/

KƏɹɅN · dəm (2 syllables)

English Noun

Definition

An extremely hard mineral, a form of aluminum oxide with the chemical formula Al₂O₃, that occurs in the form of the gemstones sapphire and ruby; it is used as an abrasive.

Etymology

From Tamil குருந்தம் (kuruntam, “ruby, sapphire”) First attested in the early 18th century.