| English | Italian | Spanish | French | German |
|---|---|---|---|---|
| English | Italian | Spanish | French | German |
| obsolete | fuori corso | fuera de curso | hors cours | ausser kurs |
| occupation | occupazione | ocupación | occupation | besetzung |
| octagonal | ottagonale | octogonal | octogone | achteckig |
| official | ufficiale | oficial | officiel | amtlich |
| official mail | posta di servizio | correo oficial | courrier de service | dienstpost |
| offset | decalco | calco | offset | abklatsch |
| on all sides | su tutti i lati | por todos los lados | de tous cótés | allseitig |
| original | originale | original | original | original |
| original gum | gomma originale | goma original | gomme initiale | ursprünglicher gummi |
| overprint | soprastampa | sobrecarga | surcharge | aufdruck |
| overprinted | soprastampato | sobreimpreso | surimprimé | aufdruckt |