1. [ noun ] (military) the act of invading; the act of an army that invades for conquest or plunder
Related terms: penetration inroad invade
2. [ noun ] any entry into an area not previously occupied
Synonyms: encroachment intrusion

"an invasion of tourists" "an invasion of locusts" "a viral invasion"

Related terms: entrance encroach
3. [ noun ] (pathology) the spread of pathogenic microorganisms or malignant cells to new sites in the body

"the tumor's invasion of surrounding structures"

Related terms: spread medicine
Similar spelling:   infusion