extratracheal

Etymology tree Proto-Indo-European *h₁éǵʰ Proto-Indo-European *-s Proto-Indo-European *h₁éǵʰs Proto-Indo-European *-teros Proto-Indo-European *h₁eǵʰsteros Proto-Italic *eksteros Latin exter Latin extrā English extra- Proto-Indo-European *dʰreh₂gʰ- Proto-Indo-European *dʰréh₂gʰ-us Proto-Hellenic *tʰrākʰús Ancient Greek τρᾱχεῖᾰ (trākheîă)bor. Late Latin trāchīa Medieval Latin trāchēader. Middle English English trachea Proto-Indo-European *h₂el-der.? Proto-Italic *-ālis Latin -ālisbor. Old French -albor. ▲ Latin -ālis Old French -elbor. ▲ Latin -ālisbor. Middle English -al English -al English tracheal English extratracheal From extra- + tracheal.

来源：wiktionary