A cipher (SY-fur) – from the Arabic for “zero” – is a secret code, usually one created using a mathematical algorithm. It can also be used to refer to someone or something of no importance.

Example: “An enormous amount of scientific language is metaphorical. We talk about a genetic code, where code originally meant a cipher; we talk about the solar system model of the atom as though the atom were like a sun and moon and planets.” (Steven Pinker)