tier /tɪə $ tɪr/ BrE AmE noun [countable]
[ Date: 1400-1500 ; Language: Old French ; Origin: tire 'order, rank' ; ⇨ ↑ attire ]
1 . one of several levels or layers that rise up one above the other:
The lower tier has 10,000 seats.
in tiers
Terraces of olive trees rose in tiers.
two-tiered/three-tiered etc (=having two, three etc levels or layers)
a three-tiered wedding cake
2 . one of several levels in an organization or system
tier of
the most senior tier of management
the first/second etc tier
The second tier of the programme is in-house training.
a two-tier system of government