\Ci"pher\, n. [OF. cifre zero, F. Chiffre figure (cf. Sp.
cifra, LL. cifra), fr. Ar. [,c]ifrun, [,c]afrun, empty,
cipher, zero, fr. [,c]afira to be empty. Cf. {Zero}.]
1. (Arith.) A character [0] which, standing by itself,
   expresses nothing, but when placed at the right hand of a
   whole number, increases its value tenfold.
2. One who, or that which, has no weight or influence.
         Here he was a mere cipher.            --W. Irving.
3. A character in general, as a figure or letter. [Obs.]
         This wisdom began to be written in ciphers and
         characters and letters bearing the forms of
         creatures.                            --Sir W.
                                               Raleigh.
4. A combination or interweaving of letters, as the initials
   of a name; a device; a monogram; as, a painter's cipher,
   an engraver's cipher, etc. The cut represents the initials
   N. W.
5. A private alphabet, system of characters, or other mode of
   writing, contrived for the safe transmission of secrets;
   also, a writing in such characters.
         His father . . . engaged him when he was very young
         to write all his letters to England in cipher. --Bp.
                                               Burnet.
{Cipher key}, a key to assist in reading writings in cipher.

\Ci"pher\, a.
Of the nature of a cipher; of no weight or influence.
``Twelve cipher bishops.'' --Milton.

\Ci"pher\, v. i. [imp. & p. p. {Ciphered}; p. pr. & vb.
n. {Ciphering}.]
To use figures in a mathematical process; to do sums in
arithmetic.
      ``T was certain he could write and cipher too.
                                               --Goldsmith.

\Ci"pher\, v. t.
1. To write in occult characters.
         His notes he ciphered with Greek characters.
                                               --Hayward.
2. To get by ciphering; as, to cipher out the answer.
3. To decipher. [Obs.] --Shak.
4. To designate by characters. [Obs.] --Shak.