1. A midline ectodermal depression ventral to the embryonic brain and surrounded by the mandibular arch; when the buccopharyngeal membrane disappears it becomes continuous with the foregut and forms the mouth.
2. The anterior portion of the insect alimentary canal, consisting of mouth, buccal cavity, pharynx, oesophagus, crop (frequently a diverticulum), and the proventriculus.
Origin: Mod. L. Fr. G. Stoma, mouth, – hodaios, on the way, fr. Hodos, a way