the act whereby any thing is inverted or turned backwards. Problems in geometry and arithmetic are often proved by inversion; that is, by a contrary rule or operation.

in Grammar, is where the words of a phrase are ranged in a manner not so natural as they might be. For an instance: "Of all vices, the most abominable, and that which least becomes a man, is impurity." Here is an inversion; the natural order being this: Impurity is the most abominable of all vices, and that which least becomes a man.—An inversion is not always disagreeable, but sometimes has a good effect.