tiered seat vs seating room

tiered seat and seating room both are nouns.

Word	Noun	Adjective	Verb	Adverb
tiered seat	Yes	No	No	No
seating room	Yes	No	No	No

As nouns, seating room is a hypernym of tiered seat; that is, seating room is a word with a broader meaning than tiered seat:

tiered seat: seating that is arranged in sloping tiers so that spectators in the back can see over the heads of those in front
seating room: an area that includes places where several people can sit

Other hypernyms of tiered seat include seating, seating area, seats.

tiered seat (noun)	seating room (noun)
seating that is arranged in sloping tiers so that spectators in the back can see over the heads of those in front	an area that includes places where several people can sit