A Gape

1. (uncommon) An act of gaping; a yawn.
2. A large opening.
3. (uncountable) A disease in poultry caused by gapeworm in the windpipe, a symptom of which is frequent gaping.
4. The width of an opening.
5. (zoology) The maximum opening of the mouth (of a bird, fish, etc.) when it is open.