Also found in: Dictionary, Thesaurus, Medical, Financial, Acronyms, Idioms, Encyclopedia, Wikipedia.
See: blank, calculate, designation, indicant, nonentity, symbol

CIPHER. An arithmetical character, used for numerical notation. Vide Figures, and 13 Vin. Ab. 210; 18 Eng. C. L. R. 95; 1 Ch. Cr. Law, 176.
     2. By cipher is also understood a mode of secret writing. Public ministers and other public agents frequently use ciphers in their correspondence, and it is sometimes very useful so to correspond in times of war. A key is given to each minister before his departure, namely, the cipher for writing ciphers, (chiffre chiffrant,) and the cipher for deciphering (chiffre dechiffrant.) Besides these, it is usual to give him a common cipher, (chiffre banal,) which is known to all the ministers of the same power, who occasionally use it in their correspondence with each other.
     3. When it is suspected that, a cipher becomes known to the cabinet where the minister is residing, recourse is had to a preconcerted sign in order to annul, entirely or in part, what has been written in cipher, or rather to indicate that the contents are to be understood in an inverted or contrary sense. A cipher of reserve is also employed in extraordinary cases.

References in classic literature ?
But, with the cipher now before us, all difficulty was removed by the signature.
Underneath is written in a hand so shaky as to be hardly legible, 'Beddoes writes in cipher to say H.
I shall require the A3X cipher, Sidney," he said to his secretary.
As you know yourself, the cipher letter warning certain people in London of the coming raid, passed through his hands.
In spite, however, of his resemblance to the handsome Russian Emperor and the terrible Domitian, Isidore Baudoyer was nothing more than a political office-holder, of little ability as head of his department, a cut-and-dried routine man, who concealed the fact that he was a flabby cipher by so ponderous a personality that no scalpel could cut deep enough to let the operator see into him.
Doubts if we could read, write, and cipher, if he tried us.
As to the cipher systems supposed to reveal hidden messages in the plays: First, no poet bending his energies to the composition of such masterpieces as Shakspere's could possibly concern himself at the same time with weaving into them a complicated and trifling cryptogram.
Fancy a man lugging with him a book of that description into this nowhere and studying it-- and making notes--in cipher at that
A cipher which he knows so well as to remember it, too
The paper which you saw me hand to the porter in the hall as we stepped into the elevator was a despatch in cipher to the English Ambassador at Washington, claiming his protection.
I cannot doubt that, if we had the cipher, we should find that this communication is of the nature that I indicate.
Give me an example of your meaning, Wamba, I know nothing of ciphers or rates of usage,'' answered the Knight.