Two corresponding persons or items, similar in form or function and matched or associated: a pair of shoes.
One object composed of two joined, similar parts that are dependent upon each other: a pair of pliers.
a. Two persons who are married, engaged, or dating.
b. Two persons who have something in common and are considered together: a pair of hunters.
c. Two mated animals.
d. Two animals joined together in work.
Games Two playing cards of the same denomination.
Two members of a deliberative body with opposing opinions on a given issue who agree to abstain from voting on the issue, thereby offsetting each other.
Usage Note: The noun pair can be followed by a singular or plural verb. The singular is always used when pair denotes the set taken as a single entity: This pair of shoes is on sale. A plural verb is used when the members are considered as individuals: The pair are working more harmoniously now. After a number other than one, pair itself can be either singular or plural, but the plural is now more common: She bought six pairs (or pair) of stockings.