Question

The space at the back of the mouth, which leads either to the airway or the esophagus is the _____.​

Answer 1

Pharynx

Pharynx — is the muscle-lined space that connects the nose and mouth to the larynx and esophagus(eating tube). Larynx — also known as the voice box, the larynx is a cylindrical grouping of cartilages, muscles and soft tissue that contains the vocal cords.

Answer 2

The part your're talking about is called the Nasal "Pharynx".