Typically used for mated animals or a matched pair of things; often seen in contexts like bird pairs or a pair of wings.
Anatomical term for a joint, such as a hinge joint in arthropods or a suture in a skull; not a common everyday word.
A pair of ducks was swimming in the pond.
This bird stays with the same mate for life.
I observed the structure of the insect leg joint.
Kana spelling is standard; the kanji forms 番い and 番 are less common.
Kanji spelling, less common than kana.
Rare kanji spelling; easily confused with 番 (ばん).
Derived from the verb 番う (つがう, 'to pair, to join'). The anatomical sense likely developed from the idea of two parts fitting together.