Whether/ˈweðər/ Definition 1 of 2Pro Tip 1/3Decision Making Used when someone is uncertain and choosing between different options. She is deciding whether to travel by train or plane. Pro Tip 2/3Including Both 'Whether or not' means both possibilities are considered, regardless of the condition. I will attend the picnic whether or not it rains. Pro Tip 3/3Indirect Questions When embedding a question within a statement, 'whether' is often used. Can you tell me whether the store is open?