Who is that? is that correct?

Answer: Yes, the phrase “Who is that?” is grammatically correct.

It is commonly used in spoken English. It is a simple and concise way to ask for the identity of a person or object. Interrogative pronouns are used for asking questions and they are called interrogative because they are used in question format. The word “who” is an interrogative pronoun used to inquire about someone’s identity, while “that” is a demonstrative pronoun used to refer to a specific person or thing. When both are combined, the phrase serves as a question seeking clarification or information about the person or object being pointed out or mentioned.

For example, if someone points to a stranger across the room, you might naturally ask, “Who is that?” to inquire about the person’s identity. Similarly, if someone is pointing at an object or an unknown entity, you could use the same phrase to ask for clarification about what they are indicating.

Overall, “Who is that?” is a concise and effective question used to gather information about someone’s identity or the identity of something being indicated.