The story
- Latinradius
- Frenchradio-
- Proto-Indo-European*h₂eǵ-
- Proto-Indo-European*h₂éǵeti
- Proto-Italic*agō
- Latinagō
- Ancient Greekἐνεργητικός (energētikós)
- Latināctīvu
- Old Frenchactif
- Frenchactif
- Frenchradioactif
- Englishradioactive
- Proto-Indo-European*leyg-
- Proto-Germanic*līką
- English todayradioactively
From radioactive + -ly.
Etymology from Wiktionary, CC BY-SA 4.0.