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*(s)tey-?
- Latinstimulus
- Latinstimulo
- Latinstimulatus
- Englishstimulate
- Englishstimulated
- English todayphotostimulated
From photo- + stimulated.
Etymology from Wiktionary, CC BY-SA 4.0.