perithyroidal

The story

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

From peri- + thyroidal.