whether Definition

1. Used to introduce an indirect question.

Example: asked whether it was raining
2. Used to introduce an indirect question involving alternative possibilities.

Example: was uncertain whether he liked her or not
3. Used to state the certainty of something, whichever of two circumstances applies.

Example: promised to marry her, whether or not his parents agreed
Example: the rules, whether fair or unfair, are not our concern
Form: whether or no (also)
Form: whether or not