Binary

In mathematics and computer science, the base-two or binary numeral system is a representation for numbers that uses only zeroes and ones as digits. See binary numeral system for detail.
In computing, a binary computer file is one that is not human-readable, especially when referring to object code versus source code. See binary and text files.
In astronomy, binary is short for binary star, a stellar system consisting of two nearby stars that revolve around a common center of mass.
In literature, a 1972 novel by Michael Crichton, writing as John Lange.