| 1 | English | on- | on, at, toward, upon |
| 2 | Middle English | on- | — |
| 3 | Old English | on- | forming verbs and adjectives from participles and... |
| 4 | Old English | and- | against, opposing; in return, back; facing,... |
| 5 | Proto-West Germanic | anda- | against, opposing; in return, back; facing,... |
| 6 | Proto-Germanic | anda- | against, opposing; un-, de- |
| 7 | Proto-Indo-European | h₂énti | opposite; near; in front |
| 8 | Proto-Indo-European | h₂énts | forehead; front |
| 9 | Proto-Indo-European | h₂ent- | face; forehead; front |
| 10 | Proto-Indo-European | h₂en- | on, onto |