One of two stars orbiting a common center of gravity: Binary stars are a pair of stars revolving around a common center of gravity, held together by their mutual gravitational interaction.

Binary stars, or a double star, is a system containing two or more stars.

In an "eclipsing binary", one star goes behind the other periodically, changing the total amount of light that we see.

A method of counting that uses only two digits: 1 and 0.

A binary star in which one component, in orbiting around the other, is totally or partially eclipsed as seen from the Earth: Jill was fascinated when she finally was able to view an eclilpsing binary where two stars were circling each other.