chestnut

Etymology

Formerly chesten nut, from Middle English chesten, Middle English chesteyne, chasteine, from Old English ċisten and reinforced by Old French chastaigne, both from Latin castānea, from Ancient Greek καστάνεια (kastáneia). Compare castanet.

noun

1. A tree or shrub of the genus Castanea.
2. A nut of this tree or shrub.
3. (uncountable) A dark, reddish-brown colour, as seen on the fruit of the chestnut tree.
   chestnut:
4. A reddish-brown horse.
   Lord Carington […] led the way with his chestnuts […] 1871, Baily's Magazine of Sports & Pastimes, volume 20, page 308
   […] browns are the soberest, bays are the worst tempered, and chestnuts are the most foolish. 1877, George Nevile, Horses and Riding, page 105
5. (uncountable) The wood of a chestnut tree.
6. (figurative) An old joke; a worn-out meme, phrase, ploy, etc. so often repeated as to have grown tiresome or ineffective (often in the phrase "old chestnut").
   Yep, this is a dance-leaning cover of the Matthew Wilder '80s pop chestnut. It has already saturated radio airwaves throughout Europe, with a number of programmers here already giving it positive feedback. 1997-05-10, Larry Flick, “Singles”, in Billboard, →ISSN, page 62
7. A round or oval horny plate found on the inner side of the leg of a horse or other animal, similar to a birthmark on a human.
8. (UK) The horse-chestnut.

adj

1. Of a deep reddish-brown colour, like that of a chestnut.
   chestnut hair