Definitions
1.nounA tree or shrub of the genus Castanea.
2.nounThe nut of this tree or shrub.
3.nounA dark, reddish-brown colour, as seen on the fruit of the chestnut tree.
4.nounA reddish-brown horse.
5.nounThe wood of a chestnut tree.
6.nounAn 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").
7.nounA 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.nounThe horse-chestnut.
9.adjectiveOf a deep reddish-brown colour, like that of a chestnut.