binary four

from Jargon File (4.4.4, 14 Aug 2003)
binary four
 n.

   [Usenet] The finger, in the sense of digitus impudicus. This comes
   from an analogy between binary and the hand, i.e. 1=00001=thumb,
   2=00010=index finger, 3=00011=index and thumb, 4=00100. Considered
   silly. Prob. from humorous derivative of {finger}, sense 4.
    

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