Who is a subject-case pronoun, meaning it functions as the subject of a sentence; the subject is the person, place, or thing that performs the action of the verb in a sentence. Whom is an object-case pronoun, meaning it functions as the object in a sentence; the object is the person, place, or thing that receives the action.
Jack is the one who informed the group of the day's activities. The subject of the sentence (Jack) performs the action (informed). Our professor, whom the class greatly respects, is retiring next year. The object of the sentence (the professor) receives the action (respect) from the class.
The English grammar rules that follow illustrate the proper ways to use who and whom: Rule 1: Subject or Object? To determine if a pronoun is the subject or object of a sentence, substitute it with "he" or "she" and "him" or "her." If "he" or "she" makes grammatical sense in the sentence, the pronoun is the subject of the verb; if "him" or "her" fits, it is the object of the verb.
Jack is the one who informed the group of the day's activities. "He" informed the group of the day's activities. Our professor, whom the class greatly respects, is retiring next year. The class greatly respects "him."
“Whom” is often the object of a verb or preposition, as in “to whom it may concern.” Rules 2: Beginning a Question Both words can be used as interrogative pronouns at the beginning of a question. If the question can be answered with a subject pronoun (he, she, it, or they), start with “who.”
Who wants to go to the zoo?He wants to go to the zoo. If the question can be answered with an object pronoun (him, her, or them), start with “whom.”
Whom did Jenn tell about the zoo? Jenn told her about the zoo.
Rules 3: Dependent Clause Who and whom can function as relative pronouns, meaning they refer to a noun or noun phrase earlier in a sentence. If a pronoun within a dependent clause (not the entire sentence) is a subject, use "who."
Stephanie is excited to meet the person who moved in next door.In the clause "who moved in next door," the subject of the sentence (person) performs the action (moved in). If a pronoun within a dependent clause (not the entire sentence) is an object, use "whom."
