wheth·er 
/ˈwɛðɚ/ conjunction
/ˈwɛðɚ/ conjunction 1 a : if it is or was true that
▪ Did you ask whether [=if] they were going? ▪ I don't know whether they were invited.
b : if it is or was better
▪ She was uncertain whether to go or stay. 2 — used to indicate choices or possibilities ▪ Whether we succeed or fail, we must try. ▪ It doesn't matter whether you pay by cash or check. ▪ We're going whether or not you decide to come along. = Whether or not you decide to come along, we're going. [=we're going if you decide to come with us and we're going if you decide not to come with us] ▪ I had to decide whether or not to respond to his letter. ▪ The police are investigating whether (or not) the death was a homicide. ▪ The game will be played whether it rains or not.
▪ Did you ask whether [=if] they were going? ▪ I don't know whether they were invited.
b : if it is or was better
▪ She was uncertain whether to go or stay.
