cipher n.

1530s, "writing in secret code or occult characters," verbal noun from cipher (v.). Meaning "action of using figures in arithmetic" is from 1610s.

"figure which stands for naught in the Arabic notation," also "the absence of all quantity considered as quantity," c. 1600, from French zéro or directly from Italian zero, from Medieval Latin zephirum, from Arabic sifr "cipher," translation of Sanskrit sunya-m "empty place, desert, naught" (see cipher (n.)).

A brief history of the invention of "zero" can be found here. Meaning "worthless person" is recorded from 1813. As an adjective from 1810. Zero tolerance first recorded 1972, originally U.S. political language. Zero-sum in game theory is from 1944 (von Neumann), indicating that if one player wins X amount the other or others must lose X amount.

1520s, "find out, discover" (a sense now obsolete); 1540s, "interpret (a coded writing, etc.) by the use of a key," from de- + cipher (v.). Perhaps in part a loan-translation from French déchiffrer. From c. 1600 in the transferred sense of "discover or explain the meaning of what is difficult to understand." Sense of "succeed in reading what is written in obscure or partially obliterated characters" is by 1710. Related: Deciphered; deciphering.