• A nut is a type of fruit borne by certain flowering plants.
• A nut is a type of hardware: a small, often hexagonal piece of metal, with a hole with internal screw thread, to be fitted onto a bolt which is inserted through holes of two or more objects, to attach these objects to each other.
• In rock climbing, a nut is a metal wedge used as protection.
• In Egyptian mythology, Nut is an alternate spelling for Nuit, (see Nuit).
• A nut is a derogative slang term for a crazy person, with the plural "nuts" used to refer to a state of insanity.
• A nut is a small strip of hard material used to stop string vibrations on some stringed instruments. It is located at the upper end of a fingerboard and, along with the bridge, defines the vibrating lengths of the strings.
• Nut is a slang term for testicle, and also for male ejaculate.
• In American English, "nuts" is a benign (i.e. non-obscene) expression of displeasure ("Aww, nuts.").
• In community card poker, having the nuts means having pocket cards that cannot be beaten given the current board (community cards).
• Nuts is the name of a British weekly men's magazine
• In typography, a nut is an en space.

See also: the acronyms NUT and NUTS.