noun an old joke or story.
2. chestnut ·noun a bright brown color, like that of the nut.
3. chestnut ·noun the horse chestnut (often so used in england).
4. chestnut ·adj of the color of a chestnut; of a reddish brown color; as, chestnut curls.
5. chestnut ·noun the tree itself, or its light, coarse-grained timber, used for ornamental work, furniture, ·etc.
6. chestnut ·noun one of the round, or oval, horny plates on the inner sides of the legs of the horse, and allied animals.
7. chestnut ·noun the edible nut of a forest tree (castanea vesca) of europe and america. commonly two or more of the nuts grow in a prickly bur.