CHESTNUT, noun The fruit, seed or nut of a tree belonging to the genus Fagus. It is inclosed in a prickly pericarp, which contains two or more seeds. CHESTNUT, adjective Being of the color of a chestnut; of a brown color. It is perhaps rarely used as a noun.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI