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cipher

American  
[sahy-fer] / ˈsaɪ fər /

noun

ciphers plural
  1. a secret method of writing or recording data, such as by substituting or adding letters or numbers, using specially formed symbols, or the like; code.

    The spies exchanged messages using a complex cipher.

    The encryption software creates unbreakable ciphers for secure communication.

  2. writing, or a piece of writing, done by a secret method; a coded message.

    Hostile agents intercepted the cipher and began trying to figure out its meaning.

  3. the key to a secret method of writing.

    After a year of studying the coded messages, the analysts were no closer to discovering the cipher.

  4. someone or something that is not understood; mystery or enigma.

    I just can’t figure him out—he’s a complete cipher to me.

  5. zero.

  6. a person or thing of no influence or importance; nonentity.

    Having lost the party leadership, she is now a mere cipher on the political scene.

  7. Usually cypher

    1. a performance by a group of rappers, hip-hop artists, or break dancers who take turns improvising individual verses, dances, etc.

    2. an individual verse, dance, etc., that is part of such a performance.

  8. any of the Arabic numerals, such as 1, 2, or 3, or any number written with such numerals, such as 476.

  9. Arabic numerical notation collectively.

    The date is MXML in Roman numerals, or 1950 in cipher.

  10. a combination of letters, such as the initials of a name, in one design; monogram.

    The cipher for Queen Elizabeth II had an E entwined with an R for regina, Latin for “queen,” on either side of a Roman numeral II.


verb (used without object)

ciphers, present (3rd person singular) ciphered, past participle, past ciphering present participle
  1. to use figures or numerals arithmetically; do arithmetic.

    He had never learned to read or write, but he could cipher.

  2. to write messages in or as if in a secret code.

verb (used with object)

ciphers, present (3rd person singular) ciphered, past participle, past ciphering present participle
  1. to convert into code; encrypt.

    The program works by ciphering or scrambling the data.

  2. to figure out the meaning of; interpret or decode (often used without ).

    Using a good phrase book, the tourist was able to cipher out what people were saying.

  3. to calculate numerically; figure (often used without ).

    I tried to cipher out the interest on the loan, compounded over five years.

cipher British  
/ ˈsaɪfə /

noun

  1. a method of secret writing using substitution or transposition of letters according to a key

  2. a secret message

  3. the key to a secret message

  4. an obsolete name for zero

  5. any of the Arabic numerals (0, 1, 2, 3, etc, to 9) or the Arabic system of numbering as a whole

  6. a person or thing of no importance; nonentity

  7. a design consisting of interwoven letters; monogram

  8. music a defect in an organ resulting in the continuous sounding of a pipe, the key of which has not been depressed

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

verb

  1. to put (a message) into secret writing

  2. (intr) (of an organ pipe) to sound without having the appropriate key depressed

  3. rare to perform (a calculation) arithmetically

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

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Etymology

Origin of cipher

First recorded in 1350–1400; Middle English siphre, from Medieval Latin ciphra, from Arabic ṣifr “empty, zero”; translation of Sanskrit śūnyā “empty”

Explanation

A cipher is a secret code, usually one that's created using a mathematical algorithm. Sometimes the message written in code is itself called a cipher. Cipher comes from the Arabic sifr, which means "nothing" or "zero." The word came to Europe along with the Arabic numeral system. As early codes substituted numerals for letters to hide the word’s meaning, codes became known as ciphers. If you crack a cipher, you break the code and can understand the message. From its "zero" meaning, cipher can also be used for a person who has no influence or importance in the world.

Keep Reading on Vocabulary.com

Vocabulary lists containing cipher

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

Frostproof became a cipher for just how untouchable the industry had become.

From Slate Apr. 20, 2026

Each letter in a standard Caesar cipher is replaced by the one three spots down the alphabet so an ‘A’ becomes a ‘D.”

From The Wall Street Journal Apr. 2, 2026

For the public’s purposes, she was a cipher onto which we were urged to project our romantic fantasies.

From Salon Feb. 12, 2026

It’s why Gere pushed for Bosko to be even more of a cipher than he was on the page.

From Los Angeles Times Jun. 11, 2025

In 1911, he had cracked Playfair, Britain’s prized military cipher, just for the fun of it.

From "The Woman All Spies Fear" by Amy Butler Greenfield

The love he once had for baseball he now felt for a strange and mysterious place that was as old as history itself yet as secretive as the classical ciphers.

From Los Angeles Times May 4, 2026

They were challenged to embed hidden codes, and ciphers into their designs.

From BBC Dec. 10, 2025

But I am calling for a little more emotional clarity from the adults who condemn these students for being imperfect ciphers of morality.

From Slate May 2, 2024

So homophonic ciphers used multiple symbols interchangeably for high-frequency letters, Lasry says.

From Scientific American Feb. 8, 2023

With insight and humor, Elizebeth and William had proved, once and for all, that Shakespeare’s plays contained no ciphers or codes.

From "The Woman All Spies Fear" by Amy Butler Greenfield

You can let a computer create various passwords and convert them into ciphered values using known hash functions.

From Scientific American Jun. 13, 2023

Also known as Mary Stuart, the then deposed queen of Scotland, who was a contender for the English throne, wrote these 57 ciphered letters between 1578 and 1584.

From Scientific American Feb. 8, 2023

The ciphered letters were believed to be Italian.

From Scientific American Feb. 8, 2023

But they were stumped by the even more complex ciphered messages being transmitted among Hitler and the generals Erwin Rommel, Wilhelm Keitel, Gerd von Rundstedt and Alfred Jodl.

From New York Times Apr. 2, 2014

Well, Sam leant back an' ciphered et out, an' cudn' see the sense o't.

From The Astonishing History of Troy Town by Quiller-Couch, Arthur Thomas, Sir

He used intricate script to write in a ciphering book, which was kept by students of the day to progress through the entirety of their mathematics education.

From Washington Post Nov. 26, 2021

He expressed his ciphering talent in an addendum to a letter his wife wrote on July 14, 1897.

From Salon Oct. 11, 2021

This reminds us of when some big, musty steamer trunk of a bill gets plopped down in Congress and the poor folks at the Congressional Budget Office get to ciphering.

From Fox News May 5, 2020

“You can tell that when me and Rondo are ciphering through our Rolodex of mental basketball capacity that those guys are like, ‘OK, what are you all talking about?’”

From Los Angeles Times Oct. 15, 2018

I liked ciphering all right, but I didn’t care much for spelling and studying the Bible and memorizing psalms.

From "My Brother Sam is Dead" by James Lincoln Collier and Christopher Collier

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