iridodiagnosis

The story

1. Englishirido-
2. Proto-Indo-European*dwóh₁
3. Proto-Indo-European*trísinflu.
4. Proto-Indo-European*dwís
5. Ancient Greekδιά (diá)
6. Ancient Greekδια- (dia-)
7. Proto-Indo-European*ǵneh₃-
8. Proto-Indo-European*ǵn̥h₃sḱéti
9. Proto-Hellenic*gignṓskō
10. Ancient Greekγῐγνώσκω (gĭgnṓskō)
11. Ancient Greekδῐαγῐγνώσκω (dĭagĭgnṓskō)
12. Ancient Greekδῐᾰ́γνωσῐς (dĭắgnōsĭs)
13. Latindiagnōsis
14. Englishdiagnosis
15. English todayiridodiagnosis

From irido- + diagnosis.