Final answer:
Yes, 'antecedent' is used correctly to refer to the noun that pronouns 'they', 'them', and 'their' replace, which must be plural. While these pronouns have traditionally been plural, they are now also used as singular gender-neutral pronouns. It's essential for pronouns to agree with their antecedents in number and gender.
Step-by-step explanation:
The word antecedent is indeed used correctly in the sentence: "The antecedent of they, them, and their must be a plural noun." An antecedent is the noun, nouns, or pronoun that a pronoun replaces, and typically appears earlier in the sentence. Since they, them, and their are pronouns that could represent plural entities, their antecedent should indeed be a plural noun. It's also important to note that while traditionally these pronouns are plural, they are also widely accepted as singular, gender-neutral pronouns in contemporary usage.
In the context of proper pronoun usage, pronoun-antecedent agreement is a fundamental rule, ensuring that pronouns match their antecedents in both number and gender. Cases where this agreement can be confusing include the use of indefinite pronouns and in sentences where the antecedent's reference is unclear.
As language evolves to become more inclusive, 'they', 'them', and 'their' have been increasingly accepted to refer to a singular individual when the gender is unknown, non-binary, or when a person prefers these gender-neutral pronouns.