Is the word their noun or pronoun?

The Word 'their' is a pronoun called a possessive adjective.

A possessive adjective is a pronoun placed before a noun to describe that noun.

The possessive adjectives are: my, your, his, her, its, our, their.

The possessive adjective 'their' is a third person, plural pronoun, a Word that takes the place of a noun for people or things spoken about.

Example: The employees look very professional in their uniforms.