Invasion \In*va"sion\, n. [L. invasio: cf. F. invasion. See
1. The act of invading; the act of encroaching upon the rights or possessions of another; encroachment; trespass. [1913 Webster]
2. A warlike or hostile entrance into the possessions or domains of another; the incursion of an army for conquest or plunder. [1913 Webster]
3. The incoming or first attack of anything hurtful or pernicious; as, the invasion of a disease.
Usage: 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. [1913 Webster]
1: the act of invading; the act of an army that invades for conquest or plunder
2: any entry into an area not previously occupied; "an invasion of tourists"; "an invasion of locusts" [syn: invasion, encroachment, intrusion]
3: (pathology) the spread of pathogenic microorganisms or malignant cells to new sites in the body; "the tumor's invasion of surrounding structures"
67 Moby Thesaurus words for "invasion": adoption, aggression, air attack, air raid, air strike, appropriation, arrogation, assault, assumption, attack, blitzkrieg, boarding, breach, drive, encroachment, entrance, entrenchment, escalade, fire raid, foray, impingement, imposition, incursion, infestation, infiltration, influx, infraction, infringement, injection, inroad, insinuation, interference, interjection, interloping, interposition, interposure, interruption, intervention, intrusion, irruption, lousiness, obtrusion, offense, offensive, onslaught, overrunning, overspreading, overswarming, plague, playing God, raid, ravage, razzia, saturation raid, scaling, seizure, shuttle raid, storming, swarm, swarming, teeming, transgression, trespass, trespassing, unlawful entry, usurpation, violation
INVASION. The entry of a country by a public enemy, making war. 2. The Constitution of the United States, art. 1, s. 8, gives power to congress "to provide for calling the militia to execute the laws of the Union, suppress insurrections, and repel invasions." Vide Insurrection.
Define Invasion and 150,000 other terms at dictionary.net