Is Were plural

It usually is. The simple past tense of "to be" can be "was" or "were." Was is used only for the first and third person singular (I, he, she, it) while were is used for all other conjugations, including plural pronouns (we, you, and they) and plural nouns (the car was, the cars were). However, the second person (you) is the same in English whether singular or plural, so "you were" could be second person singular as well.