Cipher

Cipher - Wikipedia

Etymology

Originating from the Arabic word for zero صفر (sifr), the word "cipher" spread to Europe as part of the Arabic numeral system during the Middle Ages.

The Roman numeral system lacked the concept of zero, and this limited advances in mathematics.

In this transition, the word was adopted into Medieval Latin as cifra, and then into Middle French as cifre.

This eventually led to the English word cipher (minority spelling cypher).

One theory for how the term came to refer to encoding is that the concept of zero was confusing to Europeans, and so the term came to refer to a message or communication that was not easily understood.

The term cipher was later also used to refer to any Arabic digit, or to calculation using them, so encoding text in the form of Arabic numerals is literally converting the text to "ciphers".