Principia

Principia may refer to:

• Philosophiæ Naturalis Principia Mathematica, Isaac Newton's three-volume work about his laws of motion and universal gravitation.
• Principia (lit. "primary buildings"), the headquarters at the center of Roman forts (castra)
• The Principia, and educational institution for Christian Scientists in the St. Louis, Missouri area
  • Principia College, a private four-year college in Elsah, Illinois
  • Principia School, a school from early childhood to high school in the St. Louis, Missouri area
• Principia (alga), a stem-group coralline alga
• 2653 Principia, an asteroid named after Newton's work
• The Principia (book), by Emanuel Swedenborg
• Principia Mathematica, a three-volume work on the foundations of mathematics by Bertrand Russell and Alfred North Whitehead
• Principia Ethica, a book on ethics by G.E. Moore
• Principia Discordia, a Discordian religious text by Greg Hill (Malaclypse the Younger) and Kerry Wendell Thornley (Lord Omar Khayyam Ravenhurst).
• Principia, astronaut Tim Peake's mission as part of the Expedition 46 crew of the ISS