Where does “*pro” come from?
*pro (Proto-Slavic) comes from Proto-Balto-Slavic *pra, from Proto-Indo-European pró, from Proto-Indo-European per-, from Proto-Indo-European pr̥tós — passed , crossed.
Ancestry of “*pro”, step by step
| Step | Language | Word | Meaning |
|---|
| 1 | Proto-Balto-Slavic | *pra | — |
| 2 | Proto-Indo-European | pró | toward, leading to |
| 3 | Proto-Indo-European | per- | before, in front; first; to go through |
| 4 | Proto-Indo-European | pr̥tós | passed , crossed |