nut

noun

1. the dry, one-seeded fruit of any of various trees or shrubs, consisting of a kernel, often edible, in a hard and woody or tough and leathery shell, more or less separable from the seed itself, as the walnut, pecan, chestnut, acorn, etc.
2. the kernel, or meat, of such a fruit
3. loosely any hard-shell fruit that will keep more or less indefinitely, as a peanut, almond, etc.
4. a small block, usually of metal, with a threaded hole through the center, for screwing onto a bolt, screw, etc.
5. 1. a ridge of ebony or other hard material at the top of the fingerboard of a stringed instrument, over which the strings pass
   2. the small knob at the end of a violin bow, for tightening or loosening the hairs
6. Informal the initial cost of an undertaking, or the amount of money it is necessary to take in before a profit is realized on it
7. Slang
   1. the head
   2. the testicles: a vulgar usage
8. Slang
   1. a foolish, crazy, or eccentric person
   2. a devotee; fan
9. Printing en (sense )

Etymology: ME nutte < OE hnutu, akin to Ger nuss < IE *kneu-, lump, nut (< base *ken-, to squeeze together) > L nux, MIr cnū

intransitive verb nutted nut′·ted, nutting nut′·ting