| 1 | Middle English | syns | — |
| 2 | Middle English | sithens | — |
| 3 | Middle English | sithen | From or since the time that; since then, after... |
| 4 | Old English | siþþan | afterwards, subsequently; since; ago, since |
| 5 | Old English | sīþ | journey, movement, trip, point in time, occasion;... |
| 6 | Proto-West Germanic | sinþ | journey, way, path; time, occasion |
| 7 | Proto-Germanic | sinþaz | journey, way, path; time , instance |
| 8 | Proto-Indo-European | sent- | to head for, to go, to travel; to feel |
| 9 | Proto-Indo-European | h₁es- | to be |