- 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.