noun

• (card games) A poker hand that contains two cards of identical rank, which cannot also count as a better hand.
• (cricket) A score of zero runs (a duck) in both innings of a two-innings match.
• (baseball, informal) A double play, two outs recorded in one play.
  "They turned a pair to end the fifth."
• (baseball, informal) A doubleheader, two games played on the same day between the same teams
  "The Pirates took a pair from the Phillies."

verb

• (transitive) To group into one or more sets of two.
  "The wedding guests were paired boy/girl and groom's party/bride's party."
• (computing) to link two electronic devices wirelessly together, especially through a protocol such as Bluetooth.
  "It was not possible to pair my smartphone with an incompatible smartwatch."
• (transitive) To bring two (animals, notably dogs) together for mating.
• (intransitive) To come together for mating.
  "The raven, in short, when he pairs, which he does at the earliest moment permitted by the laws of ravendom, pairs for life […]"

verb

• (obsolete, transitive) To impair, to make worse.
  "Why dreghis þou þis dole, & deris þi seluyn? / Lefe of þis Langore, as my lefe brother, / Þat puttes þe to payne and peires þi sight."
• (obsolete, intransitive) To become worse, to deteriorate.