Gape means to stare at something with your mouth hanging open, usually because you're shocked, amazed, or completely surprised. Picture a student gaping at the massive dinosaur skeleton in a natural history museum, or someone gaping at a magician who just made an elephant disappear. The mouth drops open almost automatically when something catches you completely off guard.

People often gape at things they can't quite believe: a spectacular sunset, an incredible athletic feat, or even something disturbing or frightening. The word suggests you're so absorbed in what you're seeing that you forget to close your mouth. Sometimes people will tell you “don't gape” or “stop gaping” if they think you're staring too obviously at something (or someone).

The word can also describe something that opens wide, like a gaping hole in the ground. These uses emphasize something opened so wide it's shocking or concerning. When something is agape, it means it's wide open, often in that same surprised way.