Definition of: cipher

(sī′fər) noun
1. The character 0, the symbol of the absence of quantity, in numerical notation; zero.
2. A person or thing of no value or importance.
3. A cryptogram made by re-arranging the individual characters of a plain text or by substituting others in their place.
4. The method of making such a cryptogram; also, the key for deciphering it.
5. A monogram; a character consisting of two or more interwoven or interlaced letters.
6. Any numerical character; a number. Also spelled cypher.
—v.t.
1. To calculate arithmetically.
2. To write in characters of hidden meaning; encipher.
3. To add a cipher to.
—v.i.
4. To work out arithmetical examples. [<OF cyfre <Arabic ṣifr. Doublet of ZERO.]