Merriam-Webster's Collegiate® Dictionary, 11th Edition
TIER
I. noun see: attire
Date: 1569
1. a row, rank, or layer of articles, a group of political or geographic divisions that form a row across the map , class , category ,
II. verb
Date: circa 1889
transitive verb to place or arrange in tiers, intransitive verb to rise in tiers,
III. noun or tyer
Date: 1633
one that ties