Tier

Part of speech: noun, verb

Pronunciation: /ˈtaɪ.ə/

Definitions

1. A level or position within a ranked system or hierarchy ; a horizontal row or layer of objects arranged one above another in sequence
2. A category or grade assigned in a system of classification ; a single horizontal layer stacked with others to form levels
3. One stage or division within a sequence of ranks or groups ; a set of items placed in a horizontal line forming part of a vertical arrangement

Etymology: The word "tier" has two separate histories that happen to have met in English. The noun for a layer or rank comes from Middle French "tire," meaning rank, sequence or order, which itself probably grew from "tirer," "to draw out." The idea is of things drawn into a line, one row after another, so a tier is literally a drawn-out row. That sense of order is what gives us the modern meaning of a horizontal layer stacked with others. The verb form is more familiar than it looks, because it is simply "tie" with the agent-style ending "-er" attached. A tier is a thing that ties, as in a tier of ropes or a tiered structure, and the same spelling therefore hides two unrelated roots. Readers often assume the noun and the verb must share a parent, but the noun descends from the French "tire" line instead.

Synonyms: layer, level, stratum, rank, row

Antonyms: whole, single, unity, entirety, collective