Yawning
The special tool used in the opening of the mouth during the mummification process is called the "opening of the mouth tool" or "mouth opener." This ceremonial instrument was used by the priest to perform a ritual that symbolically restored the deceased's ability to speak and eat in the afterlife. The ritual was part of the broader mummification process aimed at ensuring the deceased could navigate the afterlife successfully.
The opening is called an estuary.
The mouth.
An entrance to a cave is called a cave mouth or cave opening.
You are asking about the mouth.
umm... a mouth? a beak?
It’s called an estuary.
The opening between the mouth and the esophagus is called the pharynx.
frogs mouth part can be named as SNOUT.
The space inbetween is called the pharynx.
A deposit at the opening of a river is called delta.
It's called a tracheotomy.