# corundum

> English word · Noun · IPA /kəˈɹʌn.dəm/

## Definitions
1. 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.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/corundum