Origin: Latin suffix -sion
Invasion has 4 different meanings across 1 category:
the act of invading; the act of an army that invades for conquest or plunder
"The sudden invasion by enemy troops left the villagers scrambling to defend their homes."
any entry into an area not previously occupied
"an invasion of tourists"
"an invasion of locusts"
(pathology) the spread of pathogenic microorganisms or malignant cells to new sites in the body
"the tumor's invasion of surrounding structures"
A military action consisting of armed forces of one geopolitical entity entering territory controlled by another such entity, generally with the objective of conquering territory or altering the established government.
"The sudden invasion saw thousands of soldiers crossing the border to seize control of the neighboring capital city."
In plain English: Invasion is when someone enters another country to take control of it by force.
"The beach was full of sandpipers after their annual migration invasion from colder northern waters."
Usage: Use invasion to describe an enemy force physically crossing into your country's borders rather than a metaphorical entry. It implies a hostile takeover where troops occupy foreign soil, distinguishing it from non-military intrusions or peaceful visits.
The word entered English from the Middle French term invasion, which itself came from the Late Latin invāsiō. Originally meaning a military attack or entry by force, it traveled through French before being adopted into modern usage.