Is it someone or some one?

Someone (one word) is the correct spelling of the indefinite pronoun used to refer to an unknown or unspecified person (e.g., “Would someone answer the door?”). It is almost always the correct choice.

Some one (two words) is correct in very rare circumstances to refer to a specific but unknown person or item (e.g., “The beneficiary will be some one of his children”). This usage is unusual in modern English.

Use QuillBot’s free Grammar Checker to avoid common mistakes with indefinite pronouns.