When to use on or in question?

Question

Is it on the fitting room or in the fitting room? I would say in.

Also, is it on the living room, or in? I swear, I've heard shows where they say on the living room. Isn't it in? Can someone explain why they would say on the fitting room?

Answer 1

"In" would be the only correct usage in the examples you cite. There's really no trick - use "in" to reflect the location of something in the room, or "on" to show something is on top of it.

For instance:

"I tried on clothes in the fitting room."
"The roof on the fitting room is leaking."

Answer 2

Way I see things, nothing is ever ON the room except maybe the paint ON the walls lol. Probably another misspronunciation or bad use of grammar like many of us do, some people say 'acrossed' the street (instead of across) and it drives me nuts, but then I say a lot of funny stuff too so what can you do...