A relative pronoun is a type of pronoun that is used to connect a relative clause to a main clause. Relative pronouns introduce dependent clauses that provide additional information about a noun or pronoun in the main clause. They help to combine two ideas into a single sentence.

Here are some commonly used relative pronouns along with examples:

1. Who: Used to refer to people.

   - The woman who lives next door is a doctor.

   - He is the one who won the competition.

2. Whom: Used to refer to people, particularly in formal writing or when it is the object of a verb or preposition.

   - The man to whom I spoke is my boss.

   - She is the person whom I admire.

3. Which: Used to refer to things or animals.

   - The book, which is on the table, is mine.

   - The cat which chased the mouse is adorable.

4. That: Used to refer to people, things, or animals. It can be used in restrictive relative clauses (essential information) but is often omitted in non-restrictive clauses (non-essential information).

   - The car that I bought is red.

   - The book that I'm reading is very interesting.

5. Whose: Used to indicate possession or belonging.

   - The boy whose bicycle was stolen reported it to the police.

   - The house whose roof is damaged needs repairs.

6. Where: Used to refer to a place or location.

   - This is the school where I used to study.

   - The city where she was born is famous for its historical landmarks.

Relative pronouns not only connect the dependent clause to the main clause but also function as the subject or object within the dependent clause. They add more information, describe, or identify the noun or pronoun in the main clause.