The story
- Proto-Indo-European*bʰeh₂-
- Proto-Indo-European*bʰéh₂os
- Proto-Hellenic*pʰáwos
- Ancient Greekφᾰ́ος (phắos)
- Ancient Greekφῶς (phôs)
- Ancient Greekφωτο- (phōto-)
- Englishphoto-
- Proto-Indo-European*de
- Proto-Indo-European*déh₁
- Proto-Italic*dē
- Latindē
- Latindē-
- Englishde-
- Proto-Indo-European*wed-
- Proto-Indo-European*wódr̥
- Proto-Hellenic*údōr
- Ancient Greekῡ̆̔́δωρ (hū̆́dōr)
- Ancient Greekὑδρο- (hudro-)
- Frenchhydro-
- Proto-Indo-European*ǵenh₁-
- Proto-Indo-European*ǵénh₁os
- Proto-Hellenic*génos
- Ancient Greekγένος (génos)
- Frenchhydrogène
- Englishhydrogen
- Englishhydrogenation
- Englishdehydrogenation
- English todayphotodehydrogenation
From photo- + dehydrogenation.
Etymology from Wiktionary, CC BY-SA 4.0.