An Etymological Dictionary of Astronomy and Astrophysics

The → equivalence principle as stated by Einstein, on which is based the theory of → general relativity. It comprises
the three following items:

1. The → weak equivalence principle is valid.
   

2. The outcome of any local non-gravitational experiment is independent of the velocity of the freely-falling → reference frame in which it is performed. Also known as → local Lorentz invariance.
   

3. The outcome of any local non-gravitational experiment is independent of where and when in the Universe it is performed. Also called
   → local position invariance.

See also: → Einstein; → equivalence; → principle.