The story
- Proto-Indo-European*per-der.?
- Proto-Indo-European*pér
- Proto-Indo-European*pró
- Proto-Italic*prō
- Latinprō
- Englishpro-
- Proto-Indo-European*tres-
- Proto-Indo-European*troséyeti
- Proto-Italic*troseō
- Latinterreō
- Latinterror
- Old Frenchterreur
- Middle Frenchterreur
- Middle Englishterrour
- Englishterror
- Englishterrorist
- English todayproterrorist
Etymology from Wiktionary, CC BY-SA 4.0.