Arena seating sections (5)
I believe the answer is:
tiers
'arena seating sections' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tiers that I've seen before include "aprons for kids" , "More than one bank" , "I rest in layers" , "Layers or thicknesses" , "Tries (anag.)" .)