Pair

Pair or PAIR or Pairing may refer to:

Government and politics

Pair (parliamentary convention), matching of members unable to attend, so as not to change the voting margin
Pair, a member of the Prussian House of Lords
Pair, the French equivalent of peer, holder of a French Pairie, a French high title roughly equivalent to a member of the British peerage

2 (number), two of something, a pair
Unordered pair, or pair set, in mathematics and set theory
Ordered pair, or 2-tuple, in mathematics and set theory
Pairing, in mathematics, an R-bilinear map of modules, where R is the underlying ring
Pair type, in programming languages and type theory, a product type with two component types
Topological pair, an inclusion of topological spaces

Couple (app), formerly Pair, a mobile application for two people
PAIR (puncture-aspiration-injection-reaspiration), in medicine
Pairing, a handshaking process in Bluetooth communications
Pair programming, an agile software development technique
Pairing (computing), the linking together of devices to allow communications between them
Twisted pair, a couple of electric wires twisted together
Crew pairing, a sequence of activities a flight crew member is supposed to perform

"A pair of" can refer to one unit of certain clothing or other items. For example, "a pair of jeans" refers to one garment. Other examples include shorts, underwear, glasses, headphones, scissors, pliers, tweezers, etc.
Au pair, a work agreement
Grow a pair, referring to testicles, a slang term meaning act with more courage
Patent Application Information Retrieval, an online service providing access to the prosecution histories of U.S. patents and patent applications
Peer-Allocated Instant Response, for distance learning in the Netherlands
Wine pairing, the process of pairing food dishes with wine to enhance the dining experience