- penAn enclosure (enclosed area) used to contain domesticated animals, especially sheep or cattle.
- pennantThe broad pennant flown by commodores.
- pinionA wing.
- pennaa contour feather
- pennonA long, narrow flag or streamer, often swallowtailed or triangular, usually hung at the top of a helmet or lance, originally the ensign of a knight under the rank of knight banneret, and later of a lancer regiment.
- pennaceoushaving the structure of a normal feather
- pennageThe confining of animals in pens.
- pennalA freshman at a German university.
- pennibrachiumA forelimb, found on various species of extinct and extant coelurosaur, that is not used in flight or gliding but still bears long, typically pennaceous feathers which form a winglike surface.