Noun
(physics) the principle that an observer has no way of distinguishing whether his laboratory is in a uniform gravitational field or is in an accelerated frame of reference
Source: WordNetOther principles postulated by Einstein and later vindicated are the principle of equivalence and the principle of adiabatic invariance of the quantum number. Source: Internet
The true hallmark of poetry is according to Jakobson "the projection of the principle of equivalence from the axis of selection to the axis of combination". Source: Internet