The word "were" is the past tense form of the verb "to be." It is used as the past tense second-person singular (you were), past tense plural (we were, they were), and past subjunctive form (used in hypothetical or contrary-to-fact conditions, such as "If I were you") of "be." It serves to indicate that something happened or existed in the past. "Were" is used:

• With singular "you" in past tense: "You were late."
• With plural subjects in past tense: "They were happy."
• In hypothetical or subjunctive expressions: "If I were rich..."

The term "were" originates from Old English and is related to archaic terms like "wer," which referred to an adult male human. In modern English, "were" is primarily a grammatical verb form used to express past states or conditions and hypothetical situations.