binarity

Binarity is the state or condition of consisting of two parts, elements, or categories. The term is used across disciplines to describe dual relationships, paired components, or two-way classifications.

In astronomy, a binary star system consists of two stars bound by gravity that orbit a common center of mass. Such systems are common and crucial for determining stellar masses. Subtypes include visual binaries, where both stars are resolved; spectroscopic binaries, identified by Doppler shifts; eclipsing binaries, where mutual eclipses cause brightness changes; and astrometric binaries, inferred from the motion of a visible star. Binarity informs theories of star formation and stellar evolution.

In computing, binary refers to the base-2 numeral system used by computers. A binary digit, or bit, has the value 0 or 1; strings of bits encode numbers, text, and multimedia. Binary logic underpins digital circuits, algorithms, data storage, and communication.

In gender studies, binarity describes the division of gender into two categories, typically male and female. Critics argue that binary frameworks oversimplify human diversity and exclude non-binary, intersex, and gender-nonconforming identities. Some societies recognize more expansive gender systems, while debates about binarity influence language, policy, and social norms.

In linguistics and semiotics, binary opposition is a method of analyzing meaning via paired contrasts, such as presence/absence or life/death. Some frameworks question the universality of fixed binaries, emphasizing context, spectrum, and relationality.