No, “which” is not a preposition. It is a pronoun or a determiner, depending on how it is used in a sentence.
Uses of “Which”:
- As a Pronoun (Interrogative or Relative)
- Which is the best POS system? (Interrogative)
- The feature which improves efficiency is automation. (Relative)
- As a Determiner (Modifies a noun)
- Which restaurant do you prefer?
- She asked which menu items were the most popular.
Why “Which” Is Not a Preposition
- Prepositions show relationships between words (e.g., in, on, under, about).
- “Which” does not indicate relationships; instead, it functions as a question word (interrogative) or connector (relative pronoun).
Thus, “which” is a pronoun or a determiner, not a preposition.
