Qualifier

noun

1. One who qualifies for something, especially a contestant who qualifies for a stage in a competition.
2. A preliminary stage of a competition.
3. (grammar) A word or phrase, such as an adjective or adverb, that describes or characterizes another word or phrase, such as a noun or verb; a modifier; that adds or subtracts attributes to another.
4. A marker that qualifies or modifies another code element.