or Cypher, one of the Arabic characters, or figures, used in computation, formed thus, o. See Arithmetic.

Cipher is also a kind of enigmatic character, composed of several letters interwoven, which are generally the initial letters of the persons names for whom the ciphers are intended.

Cipher denotes likewise certain secret characters disguised and varied, used in writing letters that contain some secret, not to be understood but by those between whom the cipher is agreed on.