Other spellings cypher Pronunciation (UK) IPA (key): /ˈsaɪfə/ (US) (Canada) enPR: ˈsī-fər, IPA (key): /ˈsaɪfɚ/ Audio (UK)(file) Audio (US)(file) Hyphenation: ci‧pher Noun Singular cipher Plural ciphers A cipher is a numeric character. Synonyms: number and numeral A cipher is a method of transforming a text into a code so as to hide its meaning. Synonym: code Verb Plain form cipher Third-person singular ciphers Past tense ciphered Past participle ciphered Present participle ciphering (intransitive) If you cipher, you convert text into a code.