Ah yes. Definitions.

Who: “What person or people”

When: “At what time”

Where: “In what place or at what location”

Why: “For what reason or purpose”

How: “In what way or manner”

Hmm… Those all use “what”. Let’s go see what’s “what”.

What: “used as an interrogative expressing inquiry about…”

Thanks. That clarifies things. We don’t really know what “what” is, but we do know how it’s used.

So the next time someone asks you, “Which is the odd one out of ‘who’, ‘what’, ‘when’, ‘why’, etc.”, now you can tell them.