thyroidal

The story

1. Proto-Indo-European*dʰwer-
2. Proto-Hellenic*tʰurā
3. Ancient Greekθῠ́ρᾱ (thŭ́rā)
4. Ancient Greekθῠρεός (thŭreós)
5. Proto-Indo-European*weyd-
6. Proto-Indo-European*wéydos
7. Proto-Hellenic*wéidos
8. Ancient Greekεἶδος (eîdos)
9. Ancient Greekθῠρεοειδής (thŭreoeidḗs)
10. New Latinthyreoīdēs
11. Englishthyroid
12. Proto-Indo-European*h₂el-
13. Proto-Indo-European*h₂élisder.?
14. English todaythyroidal

From thyroid + -al.