Definitions
1.ConjunctionIntroduces a simple indirect question (without a correlative)."Whether we'll be on time I'm unsure.; Do you know whether he's coming?"
2.ConjunctionIndicates doubt between possibilities (usually with correlative or)."He chose the correct answer, but whether by luck or by skill I don't know.; I can't decide whether to get divorced now or wait."
3.ConjunctionIntroduces a disjunctive adverbial clause qualifying the main clause (with correlative or)."He's coming, whether you like it or not.; I'll enjoy playing with my friends again, whether we win or lose.; Whether or not you're successful, you can be sure you did your best."
4.ConjunctionIntroduces a direct question between alternatives (often with correlative or).
5.DeterminerWhich of two.
6.PronounWhich of two. .mw-parser-output .defdate{font-size:smaller}