Yes, “that” is one of the four most common relative pronouns in English (“that,” “which,” “who,” and “whom”).
Relative pronouns are used to introduce relative clauses, which give more information about a noun or noun phrase (e.g., “the shirt that Dylan is wearing” or “the book that is on the table”).
In other contexts, “that” is also used as an adverb, conjunction, or determiner.