"Triseriate" Natural Recordings by Native Speakers
Adjective: tri-seriate (not "triseriate" - "triseriate" is the adjectival form of the verb "triseriate")
Meaning: arranged in three rows or series; having three levels or tiers.
Example: The tri-seriate seating arrangement in the stadium allowed for optimal viewing for the audience.
Synonyms: three-tiered, triple-tiered.