A pronoun takes the place of a noun. An indefinite pronoun also takes the place of a noun – but we don’t know exactly which noun. The noun is indefinite. The pronouns anyone, everyone, someone, and no one are used to replace a noun when we don’t know who the person actually is.
I wonder if anyone will come to the concert tonight.
Everyone is busy right now.
I hope someone can hear the music.
It would be a shame if no one is there.
Use the indefinite pronouns anyone, everyone, someone, and no one when it is uncertain who the person actually is. Use a singular verb with these indefinite pronouns.
▶It’s your turn. Find the indefinite pronoun in this sentence. I have called everyone I know. Did you figure it out? Good for you!