| Part of speech | unknown part of speech |
|---|
| Singular | Plural | |
|---|---|---|
| Nominative | arko | arkoj |
| Accusative | arkon | arkojn |
| Afrikaans | boog |
|---|---|
| Catalan | arc |
| Danish | bue |
| Dutch | boog; ronding; toog |
| English | arc; bow; arch |
| English (Old English) | boga |
| Faeroese | bogi |
| Finnish | kaari |
| French | arc |
| German | Bogen; Bügel; Kreisbogen; Bogenlinie; Krümmung |
| Italian | arco |
| Latin | arcus |
| Papiamento | bog |
| Portuguese | arco |
| Romanian | bolta |
| Russian | арка; дуга |
| Saterland Frisian | Bail; Booge |
| Spanish | arco |
| Sranan | bo |
| Swedish | båge |
| West Frisian | bôge |