What does decipher mean?
To decipher something is to convert it from a puzzling or concealed form into language that can be understood. The word has two closely related uses: in cryptography, it refers to translating an encoded message back into plain text — the reverse of enciphering or encrypting it; more broadly, it describes the effort of working out the meaning of anything obscure, whether faded handwriting on a manuscript, weathered inscriptions on ancient stone, or even someone's ambiguous tone of voice. Decipher implies genuine intellectual effort: one does not merely read a deciphered text, one solves it. Historically the word is bound up with the story of codebreaking, from Renaissance ciphers to the wartime achievements of Bletchley Park, and with the great archaeological triumphs of epigraphy, such as Champollion's work on Egyptian hieroglyphs via the Rosetta Stone. Derived forms include the adjective decipherable, its negative undecipherable, and the noun decipherer. Because it connotes persistence and insight, decipher is a vivid choice whenever understanding requires real work.
To convert a coded or encrypted message into ordinary language; to decode.
"The analyst deciphered the intercepted telegram within hours."
In strict cryptographic usage, deciphering reverses a known cipher using its key, whereas cryptanalysis involves breaking a code without one.
To make out the meaning of writing, speech, or symbols that are obscure, illegible, or otherwise hard to interpret.
"Archaeologists finally deciphered the faint inscription carved above the doorway."
The word 'decipher' literally contains 'cipher' — so every time you use it, you're speaking a little bit of secret-code history.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of decipher
Decipher entered English in the early sixteenth century as the reverse of 'cipher', itself borrowed via French and medieval Latin from Arabic 'ṣifr', meaning 'zero' or 'empty'. Because numerals and then symbolic codes were associated with this Arabic root, 'cipher' came to mean a secret system of writing, and adding the prefix 'de-' produced 'decipher': literally, to undo a cipher. Its cognates include 'cipher' itself and, through the same Arabic source, words in the cryptographic family such as 'cryptography'.
Related word forms
How decipher is actually used
Decipher is standard in both British and American English and carries a neutral-to-formal register; it appears frequently in academic, historical, cryptographic, and everyday contexts where something must be laboriously worked out rather than simply read.
Easily confused with decipher
Decipher means to work out the meaning of something unclear, while deceive means to deliberately mislead someone.