Correct spelling for the English word "diaesophagus" is [dˌa͡ɪəɹɪsˈɒfəɡəs], [dˌaɪəɹɪsˈɒfəɡəs], [d_ˌaɪ_ə_ɹ_ɪ_s_ˈɒ_f_ə_ɡ_ə_s] (IPA phonetic alphabet).
A congenital reduplication, complete or partial, of the esophagus.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.