the.com/tier

means A level or rank within a graded system, where each step up usually means more quality, status, or cost than the one below it.

from From French 'tire,' meaning a row, rank, or sequence, which traces back to the verb 'tirer,' to draw or pull — as in pulling things into a line. English borrowed it in the 1500s originally to describe rows of guns on a warship or rows of seats stacked one above another, and only later did it climb into its modern life describing stacked levels of anything from cakes to credit cards.