invasion

noun

in·​va·​sion in-ˈvā-zhən 

1

: an act of invading

especially : incursion of an army for conquest or plunder

2

: the incoming or spread of something usually hurtful

Synonyms of invasion

• incursion
• raid

Examples of invasion in a Sentence

The enemy launched an invasion.

The people live under a constant threat of invasion.

The town is gearing up for the annual tourist invasion.

protecting the house from insect invasion

Recent Examples on the Web

In the mid-890s, Formosus supported King Arnulf, the leader of the Franks, in his invasion of Italy, then crowned Arnulf Roman Emperor—despite there already being a Roman Emperor. —Jane Bua, New Yorker, 20 Apr. 2026

There are also two arrests on his rap sheet for first-degree home invasion in Michigan. —Corky Siemaszko, NBC news, 20 Apr. 2026

In fact, Botanik’s entire unit of the 3rd Mountain Assault Battalion are former civilians or reservists who only made their way into the armed forces following Russia’s full-scale invasion of Ukraine. —Daria Tarasova-Markina, CNN Money, 20 Apr. 2026

Docile, furry and cute to some, possums have become an unexpected ally in the effort to slow the invasion of Burmese pythons, a snake that has decimated ecosystems in Florida. —South Florida Sun Sentinel, Sun Sentinel, 20 Apr. 2026

Word History

Etymology

Middle English invasioun "assault, attack," borrowed from Anglo-French invasion, envasioun, borrowed from Late Latin invāsiōn-, invāsiō "attack, taking possession by violence," from Latin invādere "to enter with hostile intent, assault, attack" + -tiōn-, -tiō, suffix of verbal action — more at invade

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing invasion

• counter-invasion
• invasion of (someone's) privacy
• pre-invasion

Rhymes for invasion

• abrasion
• caucasian
• equation
• eurasian
• evasion
• occasion
• persuasion
• asian
• suasion
• athanasian

Kids Definition

invasion

noun

in·​va·​sion in-ˈvā-zhən 

: an act of invading

especially : entrance of an army into a country for conquest

Medical Definition

invasion

noun

in·​va·​sion in-ˈvā-zhən 

: the act of invading: as

a

: the penetration of the body of a host by a microorganism

b

: the spread and multiplication of a pathogenic microorganism or of malignant cells in the body of a host

Legal Definition

invasion

noun

in·​va·​sion in-ˈvā-zhən 

: the act of or an instance of invading