* Noun: This is the most common use. It refers to two things that go together: "I bought a pair of shoes."
* Verb: "Pair" can mean to put two things together: "We paired the red wine with the cheese."
* Adjective: While less common, "pair" can also be used as an adjective: "We have a pair of tickets to the concert."
To figure out which part of speech it is, you need to look at how it's used in a sentence.