| Termen/ Term | Nr. apariții/ No. occurrences |
| ONOFREI MIHAIL | 4 |
| ONUFRIE IEROMONAH | 9 |
| ONUT VASILE | 1 |
| OPARICA CONSTANTIN | 2 |
| OPPENHEIMER JOSEPH | 1 |
| OPPLER ALEXANDER | 2 |
| OPREA IOAN | 1 |
| OPREA ZUGRAV | 5 |
| OPRESCU | 1 |
| OPRISAN | 1 |
| OPRISAN IULIA | 1 |
| OPRISAN LETITIA | 23 |
| OPRISOREANU ANA | 1 |
| OPROIU MARIN | 1 |
| OPRUSAN VASILE | 3 |
| OR:NEIDENTIFICAT | 1 |
| ORADEA | 29 |
| ORASANU JULIETA | 3 |
| ORASANU MATACHE | 13 |
| ORASTIE | 2 |
| ORAVITA | 1 |
| ORAVITEAN CRETU SILVIA | 1 |
| ORI | 1 |
| ORIENT JOSEF | 1 |
| ORIGINAL ETRUSC | 1 |
| ORIGINALULUI DE SEC.15 | 1 |
| ORLAI | 1 |
| ORLAI PETRICS | 1 |
| ORLAY | 1 |
| ORLIK EMIL | 2 |
| ORLITSEK F. | 2 |
| ORLOVA M. N. | 1 |
| ORLOVSCHI-BALOGH EDITH | 1 |
| ORLOWSKI | 1 |
| ORLOWSKI MIACESLAV | 5 |
| OROVEANU ION | 1 |
| ORSEL ANDRE JACQUES VICTOR | 1 |
| ORSEL ANDREE JACQUES VICTOR | 1 |
| ORTELY ABRAHAM | 1 |
| ORTGIES E. | 1 |
| ORTHI | 1 |
| ORTO UBERTO DELL' | 1 |
| ORTODOXA | 1 |
| ORVAL LEON | 1 |
| OSAKA | 2 |
| OSCAR SCHMITH | 1 |
| OSGOOD CHARLES | 1 |
| OSHIKAWA TOYONOBU | 1 |
| OSKAR NAGY | 1 |
| OSMULYCHEIEVICI | 1 |