Encyclopedias, Almanacs, Transcripts, and Maps
- Pilgrimage: Muslim Pilgrimage
- Pilgrimage: Roman Catholic Pilgrimage in Europe
- Pilgrimage: Roman Catholic Pilgrimage in the New World
- Pilgrimage: Tibetan Pilgrimage
- pilot fish
- pimpernel
- Pinard de la Boullaye, Henri
- Pinchot, Gifford (1865 – 1946) American Conservationist and Forester
- ping pong
- Pioneer program
- Pipe Snakes (Cylindrophiidae)
- Pipits and Wagtails (Motacillidae)
- Pittas (Pittidae)
- Placer Mining
- Placozoa (Placozoans)
- plaice
- Plantcutters (Phytotomidae)
- Plecoptera (Stoneflies)
- Pleuronectiformes (Flatfishes)
- Plovers and Lapwings (Charadriidae)