The NOT function indicates logical negation/complement. It can be represented by a number of notations: all of the following mean 'NOT F':
```_
F = F' = !F = ~F
```

The bar is most commonly used in digital systems, the bang is most commonly used in programming languages.

The truth table for the NOT function is:

```    _
F | F
--+--
0 | 1
1 | 0
```

In digital circuits, this function can be implemented by an inverter, and via the magic inherent in mixed logic.

See also AND, OR, NAND, NOR, XOR, NXOR, DeMorgan's Laws, logic, boolean algebra.

"Not!" as an exclamation negating the entire sentence before it was popularized by the two Wayne's World movies. So much in fact, that people here in Norway still walk around saying "NOT!".

Example : "That's a nice shirt! NOT!"

Before Wayne's World, the American band Anthrax used the expression quite a lot. They had a mascot called "The Not Man", their guitarist Scott Ian shaved "NOT" onto his chest (he is a hairy man), their merchandise t-shirts and caps had "NOT" printed on them etc. The exclamation of "NOT" was also prominent in their hit single "I am the man" (which interestingly enough precedes both Beastie Boys and Rage Against The Machine in mixing metal and rap). I once read an interview with Anthrax, where the origin of the phenomenon was discussed, and they managed to date it all the way back to 1976, remembering it being said by some kid from Brooklyn, Queens or Bronx (can't remember).

Phew, that was an interesting node. NOT!

"not" is a reserved word in the programming language Lua.

In the BNF syntax of Lua, it appears as a terminal atom in one substitution rule:
unopnot
"unop" appears as a nonterminal atom in one substitution rule:
expunop exp

"not" is the complementary unary logical operator (negation). Like the control structures, all logical operators consider "nil" as false and anything else as true. The complement operator "not" returns "nil" if its argument is different from "nil", and it returns a value other than "nil" if its argument is "nil".

In other programming languages, the "not" keyword can have another meaning: a bitwise "not" on a numeric (usually unsigned integer) operand (giving another number, of the same type, as a result). A number may be considered an array of bits; in Eindhoven notation, any number (b) may be expressed as (+ : iZ : bi * 2i) - standard binary notation - each bi being either 0 or 1, thus making an array of bits. (For signed values, the sign bit is considered just another bit in the array; for integers, negative values of i need not be considered.) The "numeric not" performs the "logical not" operation on each bit, and places the result of each "logical not" in the corresponding position in the result. In symbols, "not b" evaluates to (+ : iZ : (not bi) * 2i). This is equivalent to the ones compelement operation.

The C symbol for "numeric not" (or "ones complement") is !. There is no C symbol for "logical not", except that "numeric not" works equivalently on boolean types or when 0 is used for "false" and -1 is used for "true".

Not (?). [Contr. from ne wot. See 2d Note.]

Wot not; know not; knows not.

[Obs.]

Chaucer.

Not, a.

Shorn; shaven. [Obs.] See Nott.

Not, adv. [OE. not, noht, nought, naught, the same word as E. naught. See Naught.]

A word used to express negation, prohibition, denial, or refusal.

Not one word spake he more than was need. Chaucer.

Thou shalt not steal. Ex. xx. 15.

Thine eyes are upon me, and I am not. Job vii. 8.

The question is, may I do it, or may I not do it? Bp. Sanderson.

Not . . . but, ∨ Not but, only. [Obs. or Colloq.]

Chaucer.