Parentless Concepts
- Norton
- Nostitz, Otto von
- not applicable (or unknown)
- Novigrad
- Numisma Arabicum cum expositione Itali cuiusdam
- Nuremberg
- Obelius
- Oertel, Hieronymus
- ogg
- Old Testament in Arabic
- Omar & Ossman & Aly carmina
- Opala, Elias
- open access
- opera
- Opus Veteris Testamenti Arabicum, praecipue Prophaetae
- Orient
- original
- Orlandini, Nicolò
- Orta, Garcia de
- Osiander, Andreas
- Osman II
- Osóno, Jerónimo
- Ostermayer, Gerardus
- Ostermayr, Gerhard