tiered seat vs seats

tiered seat and seats both are nouns.

Word	Noun	Adjective	Verb	Adverb
tiered seat	Yes	No	No	No
seats	Yes	No	No	No

As nouns, seats is a hypernym of tiered seat; that is, seats 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
seats: an area that includes places where several people can sit

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

tiered seat (noun)	seats (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