Webster's Revised Unabridged Dictionary · 1913

Usurpation

Usurpation , noun

[Latin usurpatio {not transcribed} making use, usurpation: compare French usurpation.]

1.
The act of usurping, or of seizing and enjoying; an authorized, arbitrary assumption and exercise of power, especially an infringing on the rights of others; specifically, the illegal seizure of sovereign power; -- commonly used with of, also used with on or upon; as, the usurpation of a throne; the usurpation of the supreme power.
He contrived their destruction, with the usurpation of the regal dignity upon him. — Sir T. More
A law [of a State] which is a usurpation upon the general government. — O. Ellsworth
Manifest usurpation on the rights of other States. — D. Webster

Usurpation, in a peculiar sense, formerly denoted the absolute ouster and dispossession of the patron of a church, by a stranger presenting a clerk to a vacant benefice, who us thereupon admitted and instituted.

2.
Use; usage; custom. [Obsolete] — Bp. Pearson