| 1 | Middle English | single | — |
| 2 | Old French | sengle | single; alone; alone; in an unaccompanied way |
| 3 | Late Latin | cingula | nominative/accusative/vocative plural of cingulum |
| 4 | Latin | Cingulum | — |
| 5 | Latin | -ulum | Used to form a noun of instrument or means from a... |
| 6 | Proto-Indo-European | -tlom | Alternative form of *-trom |
| 7 | Proto-Indo-European | -trom | Forms nouns denoting a tool or instrument |
| 8 | Proto-Indo-European | -tḗr | Derives agent nouns from verbs, denoting someone... |