Is are a verb or a noun?

Answer 1

The word 'are' is a verb, a form of the verb 'to be'.

Examples:

I am

you are

he, she, it is

we are

you are

they are

The verb 'are' often functions as an auxiliary (helper) verb.

Example: We are walking to school. or: They are working on the road.

The verb 'are' also functions as a linking verb when the direct object of the verb renames the subject of the sentence.

Example: Mary is my sister (Mary = sister), or: My feet are wet. (feet = wet)

Answer 2

Are, as in "they are big" is a verb.But are is also a unit of measure of area and in that context it is a noun.