The story
- Proto-Indo-European*bʰeh₂-
- Proto-Indo-European*bʰéh₂os
- Proto-Hellenic*pʰáwos
- Ancient Greekφᾰ́ος (phắos)
- Ancient Greekφῶς (phôs)
- Ancient Greekφωτο- (phōto-)
- Englishphoto-
- Frenchélectro-
- Latinēlectrum
- Latinelectro-
- Englishelectro-
- Latināctīvitās
- Middle Frenchactivité
- Englishactivity
- Englishelectroactivity
- English todayphotoelectroactivity
From photo- + electroactivity.
Etymology from Wiktionary, CC BY-SA 4.0.