The Collaborative International Dictionary
Subesophageal
Subesophageal \Sub*e`so*phag"e*al\, a. (Zo["o]l.) Situated beneath the esophagus. [Written also sub[oe]sophageal.]
Subesophageal ganglion (Zo["o]l.), a large special ganglion situated beneath the esophagus of arthropods, annelids, and some other invertebrates.
Wiktionary
subesophageal
a. (context anatomy English) Situated beneath the esophagus.