nut

noun

• 1a fruit consisting of a hard or tough shell around an edible kernel: he was cracking nuts with his teeth
• the hard kernel of a nut: savoury snacks like crisps and nuts
• (usually nuts) a small lump of something hard or solid, especially coal.

• 2a small flat piece of metal or other material, typically square or hexagonal, with a threaded hole through it for screwing on to a bolt as a fastener: fix the new pipe and tighten the nuts the final wheel nut was tightened
• the part at the lower end of the bow of a violin or similar instrument, with a screw for adjusting the tension of the hair.

• 3 informal a crazy or eccentric person: she would have written me off as a time-wasting nut
• [with adjective or noun modifier] a person who is excessively interested in or enthusiastic about a specified thing:a football nut

• 4 informal a person’s head: he’s aiming to break a record by balancing a car on his nut

• 5 (nuts) vulgar slang a man’s testicles.

• 6the fixed ridge on the neck of a stringed instrument over which the strings pass: the positioning allows the strings a straight path over the nut

verb (nuts, nutting, nutted)

• 1 [with object] British informal butt (someone) with one’s head: I thought he was going to nut me in the face

• 2 [no object] (usually as noun nutting) archaic gather nuts.