intratracheal

The story

1. Proto-Indo-European*h₁én
2. Proto-Indo-European*h₁énteros
3. Latin*interus
4. Latinintrā
5. Englishintra-
6. Proto-Indo-European*dʰreh₂gʰ-
7. Proto-Indo-European*dʰréh₂gʰus
8. Proto-Hellenic*tʰrākʰús
9. Ancient Greekτρᾱχεῖᾰ (trākheîă)
10. Late Latintrāchīa
11. Medieval Latintrāchēa
12. Englishtrachea
13. Proto-Indo-European*h₂el-
14. Proto-Indo-European*h₂élisder.?
15. Englishtracheal
16. English todayintratracheal

From intra- + tracheal.