| Termen/ Term | Nr. apariții/ No. occurrences |
| ONCE PETRE | 1 |
| OLTENIA | 2 |
| OKAJIMA TOJIRO | 3 |
| O | 1 |
| O'CONNOR | 1 |
| O'HIGGINS PABLO | 8 |
| O. ELLGERS | 1 |
| OA RIOS LUIGI | 1 |
| OANCEA TRAIAN | 1 |
| OBEDEANU OSCAR | 94 |
| OBEDENARU OSCAR | 2 |
| OBERMULLNER ADOLF | 1 |
| OBRECHKOV B | 3 |
| OBRESCOV BENCIO | 1 |
| OCHIAI YOSHIIKU | 3 |
| OCHME ERNST ERVIN | 1 |
| OCNELE | 12 |
| OCNELE MARI | 3 |
| OCNER I.A. | 1 |
| OCTAV BANCILA | 5 |
| OCTAV DIOCESCU | 2 |
| ODINTOV V. V. | 1 |
| ODOBESCU RADU | 1 |
| ODON MIKLOSI | 1 |
| ODOSIE | 1 |
| ODRY IOSIF | 2 |
| OECONOMO A. | 1 |
| OEDER L. | 5 |
| OER TH. V. | 1 |
| OESER | 2 |
| OGATA GEKKO | 3 |
| OGATA KENZAN | 1 |
| OHARAN LETICIA | 2 |
| OKAKUNI KICHIBEI | 1 |
| OKAZAWAYA TAHEIJI | 2 |
| OKINOBU | 1 |
| OKUHACHI | 2 |
| OKUHACHI DIN | 1 |
| OLAC VASILE | 3 |
| OLANDA | 1 |
| OLANDEZA | 18 |
| OLANU | 1 |
| OLARIAN MIRCEA | 94 |
| OLARIU DANA | 1 |
| OLARIU IULIAN | 130 |
| OLARIU JULIAN | 2 |
| OLARIU MIRCEA | 7 |
| OLARIU OCTAVIAN | 2 |
| OLDERMANN F. | 2 |
| OLESYNSKI | 1 |