原理

principle / theory

surname Yuan / (Japanese surname) Hara

former / original / primary / raw / level / cause / source

texture / grain (of wood) / inner essence / intrinsic order / reason / logic / truth / science / natural science (esp. physics) / to manage / to pay attention to / to run (affairs) / to handle / to put in order / to tidy up

(Pauli) exclusion principle (physics)

Heisenberg's uncertainty principle (1927)

fundamental principle

variational principle (physics)