Where does “er-” come from?
er- (Middle High German) comes from Old High German ir-, from Proto-West Germanic uʀ-, from Proto-Germanic uz-, from Proto-Indo-European uss-, from Proto-Indo-European uds-, from Proto-Indo-European úd — out, outward.
Ancestry of “er-”, step by step
| Step | Language | Word | Meaning |
|---|
| 1 | Old High German | ir- | thoroughly |
| 2 | Proto-West Germanic | uʀ- | out, over; off, away |
| 3 | Proto-Germanic | uz- | up, out |
| 4 | Proto-Indo-European | uss- | — |
| 5 | Proto-Indo-European | uds- | up, out |
| 6 | Proto-Indo-European | úd | out, outward |