Word Origin & History
1570, from chesten nut (1519), from M.E. chasteine, from O.Fr. chastaigne, from L. castanea, from Gk. kastaneia, which the Greeks thought meant either "nut from Castanea" in Pontus, or "nut from Castana" in Thessaly, but probably both places are named for the trees, not the other way around, and the
word is probably borrowed from a language of Asia Minor. Of the dark reddish-brown color, 1656. Applied to the horse-chestnut 1832. Slang sense of "venerable joke or story" is from 1886, probably from a joke (first recorded 1888) based on an oft-repeated story in which a chestnut tree figures. The key part of the 1888 citation is:
"When suddenly from the thick boughs of a cork-tree --"
"A chestnut, Captain; a chestnut."
"Bah! booby, I say a cork-tree!"
"A chestnut," reiterates Pablo. "I should know as well as you, having heard you tell the tale these twenty-seven times."