whether

Từ điển Oxford Advanced Learner 8th

whether BrE [ˈweðə(r)] NAmE [ˈweðər] conjunction
1. used to express a doubt or choice between two possibilities
• He seemed undecided whether to go or stay.
• It remains to be seen whether or not this idea can be put into practice.
•I asked him whether he had done it all himself or whether someone had helped him.
•I'll see whether she's at home (= or not at home).
•It's doubtful whether there'll be any seats left.
2. used to show that sth is true in either of two cases
• You are entitled to a free gift whether you accept our offer of insurance or not.
• I'm going whether you like it or not.
•Whether or not we're successful, we can be sure that we did our best.

Word Origin:
[whether] Old English hwæther, hwether, of Germanic origin; related to German weder ‘neither’.

Grammar Point:
if / whether
Both if and whether are used in reporting questions which expect ‘yes’ or ‘no’ as the answer: ▪ She asked if/whether I wanted a drink., although whether sounds more natural with particular verbs such as discuss, consider and decide. When a choice is offered between alternatives if or whether can be used: ▪ We didn’t know if/whether we should write or phone. In this last type of sentence, whether is usually considered more formal and more suitable for written English.