In*va"sion (?), n. [L. invasio: cf. F. invasion. See Invade.]
1.
The act of invading; the act of encroaching upon the rights or possessions of another; encroachment; trespass.
2.
A warlike or hostile entrance into the possessions or domains of another; the incursion of an army for conquest or plunder.
3.
The incoming or first attack of anything hurtful or pernicious; as, the invasion of a disease.
Syn. -- Invasion, Irruption, Inroad. Invasion is the generic term, denoting a forcible entrance into a foreign country. Incursion signifies a hasty and sudden invasion. Irruption denotes particularly violent invasion. Inroad is entry by some unusual way involving trespass and injury.
© Webster 1913.