| noun | the act of invading; the act of an army that invades for conquest or plunder |
| noun | any entry into an area not previously occupied “an invasion of tourists” |
| noun | (pathology) the spread of pathogenic microorganisms or malignant cells to new sites in the body “the tumor's invasion of surrounding structures” |
| invade | verb | march aggressively into another's territory by military force for the purposes of conquest and occupation |
| encroach | verb | advance beyond the usual limit |