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English definition of “cipher”

cipher

noun uk   /ˈsaɪ.fər/ us    /-fɚ/

cipher noun (SECRET LANGUAGE)

[C or U] (also cypher) a system of writing that prevents most people from understanding the message: The message was written in cipher.
Synonym
Codes and decodingSigns, signals and symbols

cipher noun (PERSON)

[C] formal disapproving a person or group of people without power, but used by others for their own purposes, or someone who is not important: The interim government is a mere cipher for military rule.People of little importance

cipher noun (NUMBER)

[C] US a zero: If you have no children, enter a cipher in the space on the form.Cardinal numbers, including nought and zero
(Definition of cipher from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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