Is “which” a subordinating conjunction?
No, which is classified as a relative pronoun. Although a relative clause is a type of dependent clause, a relative pronoun is not the same as a subordinating conjunction because it acts as a subject/object or refers back to a noun, whereas a subordinating conjunction is a linking device.
It is also used as an interrogative word (e.g., “Which shirt looks best?”).
Sometimes people confuse wich or which, but the correct spelling is always which.
The QuillBot Grammar Checker can help ensure you’re using relative pronouns and interrogative words correctly.