Open English Wordnet
Nouns
(n)grade, level, tier1a relative position or degree of value in a graded group“lumber of the highest grade” (n)tier1any one of two or more competitors who tie one another (n)tier1one of two or more layers one atop another“tier upon tier of huge casks”,
“a three-tier wedding cake” (n)tier2something that is used for tying“the sail is fastened to the yard with tiers”