| 1 | Middle English | devoir | devoir |
| 2 | French | devoir | duty; exercise, assignment; must, to have to,... |
| 3 | Italian | dovere | to owe; to have to do something; duty |
| 4 | Spanish | deber | obligation, duty; debt; should, ought |
| 5 | Old Spanish | dever | — |
| 6 | Latin | dēbeō | — |
| 7 | Latin | dē- | — |
| 8 | Latin | dē | — |
| 9 | Latin | post | behind; after, since, besides, except; behind,... |
| 10 | Latin | poste | ablative singular of postis |
| 11 | Proto-Italic | posti | — |
| 12 | Proto-Indo-European | pósti | — |
| 13 | Proto-Indo-European | pós | afterwards, post; by, at |