| Principal bundle | Fibrado principal |
| principal character | héroe |
| Principal Charming | Principal Charming |
| principal clause | oración principal |
| Principal components analysis | Análisis de componentes principales |
| principal dish | plato principal |
| principal parts | partes principales |
| Principal-agent problem | Problema del agente-principal |
| principality | principado |
| Principality of Andorra | Andorra |
| Principality of Ansbach | Ansbach |
| Principality of Antioch | Principado de Antioquía |
| Principality of Bayreuth | Bayreuth |
| Principality of Capua | Principado de Capua |
| Principality of Catalonia | Principado de Cataluña |
| Principality of Freedonia | Principado de Freedonia |
| Principality of Galilee | Principado de Galilea |
| Principality of Liechtenstein | Liechtenstein |
| Principality of Lippe | Distrito de Lippe |
| Principality of Moldavia | Moldavia |
| Principality of Moscow | Principado de Moscú |
| Principality of Orange | Estado Libre de Orange |
| Principality of Pindus and Voivodship of Macedonia | Principado del Pindo y Voivodía de Macedonia |
| Principality of Sealand | Sealand |
| Principality of Seborga | Seborga |
| Principality of Serbia | Principado de Serbia |
| Principality of Theodoro | Principado de Teodoro |
| Principality of Zeta | Zetta |
| principally | principalmente |
| Principe de Asturias | Príncipe de Asturias |
| Principense language | Idioma principense |
| Principes | Principes |
| Principia Mathematica | Principia Mathematica |
| principle | principio |
| principle article | artículo de primera plana |
| Principle of bivalence | Lógica bivalente |
