• pair plural pairs or pair [countable]
• 1

  joined together

   an object that is made from two similar parts that are joined together
• pair of trousers/scissors/glasses etc
• two pairs of jeans
• a pair of black tights
• 2

  belonging together

   two things of the same type that are used together
• pair of
• a new pair of sandals
• pair of hands/eyes/legs etc
• She felt as if every pair of eyes in the room was on her.
• earrings, £5 a pair
• a pair of skis
• We have five pairs of free tickets to give away.
• 3

  in pairs

   in groups of two:
• We worked in pairs for the role-play exercise.
• The leaves of the tree are arranged in pairs.
• 4

  two people

   two people who are standing or doing something together, or who have some type of connection with each other [↪ couple]:
• The pair are looking for sponsorship from local businesses.
• pair of
• a pair of dancers
• ! Do not use pair to talk about a husband and wife (or two people in a similar relationship). Use couple: They're such a nice couple (NOT pair).
• 5

  the pair of you/them

  British English spoken used when you are angry or annoyed with two people:
• Oh, get out, the pair of you.
• 6

  two animals

• a) a male and a female animal that come together in order to breed
• pair of
• a pair of doves
• a breeding pair
• b) old use two horses that work together
• 7

  I've only got one pair of hands

  spoken used to say that you are busy and cannot do any more than you are already doing
• 8

  an extra pair of hands

   someone who helps you do something when you are busy:
• Having an extra pair of hands during busy periods can take the pressure off.
• 9

  a safe pair of hands

   someone you can trust and depend on because they are sensible - used especially in news reports:
• Colleagues regard him as a safe pair of hands.

Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary.