1. [n]  the cutting part of a drill; usually pointed and threaded and is replaceable in a brace or bitstock or drill press; "he looked around for the right size bit"
2. [n]  piece of metal held in horse's mouth by reins and used to control the horse while riding; "the horse was not accustomed to a bit"
3. [n]  a short theatrical performance that is part of a longer program; "he did his act three times every evening"; "she had a catchy little routine"; "it was one of the best numbers he ever did"
4. [n]  a small fragment; "overheard snatches of their conversation"
5. [n]  an instance of some kind; "it was a nice piece of work"; "he had a bit of good luck"
6. [n]  a small amount of solid food; a mouthful; "all they had left was a bit of bread"
7. [n]  a small fragment of something broken off from the whole; "a bit of rock caught him in the eye"
8. [n]  a unit of measurement of information (from Binary + digIT); the amount of information in a system having two equiprobable states; "there are 8 bits in a byte"
9. [n]  (British) a small quantity; "a spot of tea"; "a bit of paper"
10. [n]  an indefinitely short time; "wait just a moment"; "it only takes a minute"; "in just a bit"
11. [adj]  injured by bites or stings; "leaving the biter bit"; "her poor mosquito-bitten legs"

1. \Bit\, n. [OE. bitt, bite, AS. bite, bite, fr. b[=i]tan to
   bite. See {Bite}, n. & v., and cf. {Bit} a morsel.]
   1. The part of a bridle, usually of iron, which is inserted
      in the mouth of a horse, and having appendages to which
      the reins are fastened. --Shak.
            The foamy bridle with the bit of gold. --Chaucer.
   2. Fig.: Anything which curbs or restrains.
   

2. \Bit\, v. t. [imp. & p. p. {Bitted}; p. pr. & vb. n.
   {Bitting}.]
   To put a bridle upon; to put the bit in the mouth of.
   

3. \Bit\,
   imp. & p. p. of {Bite}.
   

4. \Bit\, n. [OE. bite, AS. bita, fr. b[=i]tan to bite; akin to
   D. beet, G. bissen bit, morsel, Icel. biti. See {Bite}, v.,
   and cf. {Bit} part of a bridle.]
   1. A part of anything, such as may be bitten off or taken
      into the mouth; a morsel; a bite. Hence: A small piece of
      anything; a little; a mite.
   2. Somewhat; something, but not very great.
            My young companion was a bit of a poet. --T. Hook.
   Note: This word is used, also, like jot and whit, to express
         the smallest degree; as, he is not a bit wiser.
   3. A tool for boring, of various forms and sizes, usually
      turned by means of a brace or bitstock. See {Bitstock}.
   4. The part of a key which enters the lock and acts upon the
      bolt and tumblers. --Knight.
   5. The cutting iron of a plane. --Knight.
   6. In the Southern and Southwestern States, a small silver
      coin (as the real) formerly current; commonly, one worth
      about 12 1/2 cents; also, the sum of 12 1/2 cents.
   {Bit my bit}, piecemeal. --Pope.
   

5. \Bit\,
   3d sing. pr. of {Bid}, for biddeth. [Obs.] --Chaucer.
   

6. \Bit\, n.
   In the British West Indies, a fourpenny piece, or groat.
   

(b) binary digit.

The unit of information; the amount of information obtained by asking a yes-or-no question; a computational quantity that can take on one of two values, such as false and true or 0 and 1; the smallest unit of storage - sufficient to hold one bit.

A bit is said to be "set" if its value is true or 1, and "reset" or "clear" if its value is false or 0. One speaks of setting and clearing bits. To toggle or "invert" a bit is to change it, either from 0 to 1 or from 1 to 0.

The term "bit" first appeared in print in the computer-science sense in 1949, and seems to have been coined by the eminent statistician, John Tukey. Tukey records that it evolved over a lunch table as a handier alternative to "bigit" or "binit".

See also flag, trit, mode bit, byte, word.

[Jargon File]

the curb put into the mouths of horses to restrain them. The Hebrew word (metheg) so rendered in Ps. 32:9 is elsewhere translated "bridle" (2 Kings 19:28; Prov. 26:3; Isa. 37:29). Bits were generally made of bronze or iron, but sometimes also of gold or silver. In James 3:3 the Authorized Version translates the Greek word by "bits," but the Revised Version by "bridles."