cipher

Etymology

14th century. From Middle English cifre, from Old French cyfre, cyffre (French chiffre), ultimately from Arabic صِفْر (ṣifr, “zero, empty”), from صَفَرَ (ṣafara, “to be empty”). Doublet of zero. Sense 9 may be a different word.

noun

1. A numeric character.
2. Any text character.
3. A combination or interweaving of letters, as the initials of a name.
   a painter's cipher
   an engraver's cipher
4. A method of transforming a text in order to conceal its meaning.
   The message was written in a simple cipher. Anyone could figure it out.
5. (cryptography) A cryptographic system using an algorithm that converts letters or sequences of bits into ciphertext.
   a public-key cipher
6. Ciphertext; a message concealed via a cipher.
   The message is clearly a cipher, but I can't figure it out.
7. A grouping of three digits in a number, especially when delimited by commas or periods:
   The probability is 1 in 1,000,000,000,000,000 — a number having five ciphers of zeros.
8. (music) A fault in an organ valve which causes a pipe to sound continuously without the key having been pressed.
9. (music, slang) A hip-hop jam session.
   They say no girls in the cipher, so I rock solo 2011, “The World Is Listening”, in The Journey Aflame, performed by Akua Naru
10. (slang) The path (usually circular) shared cannabis takes through a group, an occasion of cannabis smoking.
    As the night seemed darker, cops is on a hunt / They interrupt your cipher, and crush your blunt 1993, “Midnight”, performed by A Tribe Called Quest
11. Someone or something of no importance.
12. (dated) Zero.
13. Eggcorn of siphon.

verb

1. (intransitive, regional, dated) To calculate.
   I never learned much more than how to read and cipher.
   Can you cipher too—along with your reading and writing? 1979, Octavia Butler, Kindred
2. (intransitive) To write in code or cipher.
3. (intransitive, music) Of an organ pipe: to sound independent of the organ.
4. (obsolete) To decipher.