used to introduce two or more possibilities or to show doubt between alternatives
She's not sure whether to study medicine or engineering.
Do you know whether he called last night?
✦ Old English hwæther, from Proto-Germanic *hwatara “which of two”.
used to say that it makes no difference which of the alternatives is true, often followed by “or not”
We're going hiking tomorrow whether it rains or not.
I'll support you whether you succeed or fail.
✦ Old English hwæther, same root as the alternative-introducing sense, later broadened to express indifference to outcome.
