tier 
/ˈtiɚ/ noun
plural tiers /ˈtiɚ/ noun [count] 1 : a row or layer of things that is above another row or layer
▪ We were seated in the theater's top tier. 2 : a particular level in a group, organization, etc.
▪ top tier colleges [=the best or most expensive colleges] ▪ the lowest tier of management
▪ We were seated in the theater's top tier.
▪ top tier colleges [=the best or most expensive colleges] ▪ the lowest tier of management
