Awe is a feeling of fear that is mixed with respect and wonder. You might gaze at the Grand Canyon with awe, marveling at its beauty and fearing its depth.
Awe dates back to Middle English, and was borrowed from Old Norse, a Scandinavian language. In Middle English the word referred to intense fear. The related English word awful originally meant "full of or causing intense fear." And awesome, which originally meant "inspiring awe" now is used generally as a synonym for excellent.