n. & adj.
n. 1 a a glossy hard brown edible nut. b the tree Castanea sativa, bearing flowers in catkins and nuts enclosed in a spiny fruit. Also called Spanish chestnut or sweet chestnut. 2 any other tree of the genus Castanea. 3 = horse chestnut. 4 (in full chestnut-wood) the heavy wood of any chestnut tree. 5 a horse of a reddish-brown or yellowish-brown colour. 6 colloq. a stale joke or anecdote. 7 a small hard patch on a horse's leg. 8 a reddish-brown colour.
adj. of the colour chestnut. liver chestnut a dark kind of chestnut horse.
[ obs. chesten f. OF chastaine f. L castanea f. Gk kastanea ]