Where does “pro” come from?
pro (Latin) comes from Latin ratus, from Latin rēōr, from Proto-Italic rēōr, from Proto-Indo-European h₂reh₁-, from Proto-Indo-European h₂er- — to fit, to fix, to put together.
Ancestry of “pro”, step by step
| Step | Language | Word | Meaning |
|---|
| 1 | Latin | ratus | considered, having been considered; established,... |
| 2 | Latin | rēōr | — |
| 3 | Proto-Italic | rēōr | to reckon, to calculate; to think, to deem, to... |
| 4 | Proto-Indo-European | h₂reh₁- | to think, reason; to arrange |
| 5 | Proto-Indo-European | h₂er- | to fit, to fix, to put together |