The word "are" is a form of the verb "to be," used primarily in the present tense. It serves as a linking verb that connects the subject of a sentence to a complement, indicating existence or a state of being. For example, in the sentence "They are happy," the word "are" links the subject they to the adjective happy. In English grammar, "are" is used with plural subjects and the pronoun you. It helps to describe characteristics, conditions, or identities. For instance, "The dogs are playful" shows the relationship between the subject the dogs and the adjective playful.