Nut (fruit) , a type of fruit borne by certain flowering plants
Nut (hardware), 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
Nut (climbing), a metal wedge used as protection during rock climbing
Nut (instrumental), 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" also refers to the device at the end of the bow that tightens or loosens the hairs.
NUT Container, an audio/video container format used in the multimedia field
Nut hand, a hand of cards in community card poker having pocket cards that cannot be beaten given the current board