Encyclopedias, Almanacs, Transcripts, and Maps
- Prothero, Rowland Edmund
- Protić, Stojan
- Protich, Stojan
- protoactinium
- Protogenes
- proton-proton cycle
- protonation
- protoplanet theory
- Protopopov, Aleksandr Dmitreyevich
- Prout, Father
- Provençal language
- Provençal literature
- Province Wellesley
- Provincetown
- Provoost, Samuel
- Prudhoe Bay
- Prus, Bolesław
- Prusa
- prussic acid
- Prutkov, Kozma