Hunspell - The most popular spellchecking library

Hunspell is a spell checker and morphological analyzer library and program designed for languages with rich morphology and complex compounding or character encoding. Hunspell interfaces: Curses, Ispell compatible pipe interface, OpenOffice.org UNO module.

Hunspell is the spell checker of LibreOffice, OpenOffice.org, Mozilla Firefox 3 & Thunderbird, Google Chrome, and it is also used by proprietary software packages, like macOS, InDesign, memoQ, Opera and SDL Trados.