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.

   “But England's final qualifier, played out in the hostile surroundings of Podgorica City Stadium, turned on two incidents that will have cast a cloud over Capello's delight at reaching another major tournament.”

   “Rice is maturing at such a rate that he is now indispensable. Yes, these qualifiers may not be the most exacting examinations but he has also looked a class act at club level under manager David Moyes this season.”

3. A word or phrase, such as an adjective or adverb, that describes or characterizes another word or phrase, such as a noun or verb; one that adds or subtracts attributes to another.
4. A marker that qualifies or modifies another code element.

   “The qualifier const may be prefixed to any declaration, and specifies that the value to which the data object is initialised cannot subsequently be changed.”