| 1 | Irish | os- | over-, above; super-, supra- |
| 2 | Irish | ós | since... is; Alternative form of ó; mouth |
| 3 | Old Irish | úas | above, over |
| 4 | Dutch | wassen | to wash, to clean; to grow, to rise, to increase,... |
| 5 | Dutch | was | laundry, clothes that need to be washed, or just... |
| 6 | Middle Dutch | was | first/third-person singular past indicative of... |
| 7 | Middle Dutch | wassen | to grow, to wax; to increase |
| 8 | Old Dutch | wassan | to grow, to wax; to rise in level |
| 9 | Proto-West Germanic | wahsan | to grow |
| 10 | Proto-Germanic | wahsijaną | to grow |
| 11 | Indo-European | *h₂weks- | — |