invasion

American  

[in-vey-zhuhn] / ɪnˈveɪ ʒən /

noun

1. an act or instance of invading or entering as an enemy, especially by an army.

2. the entrance or advent of anything troublesome or harmful, as disease.

3. entrance as if to take possession or overrun.

   the annual invasion of the resort by tourists.

4. infringement by intrusion.

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invasion British  

/ ɪnˈveɪʒən /

noun

1. the act of invading with armed forces

2. any encroachment or intrusion

   an invasion of rats

3. the onset or advent of something harmful, esp of a disease

4. pathol the spread of cancer from its point of origin into surrounding tissues

5. the movement of plants to a new area or to an area to which they are not native

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Other Word Forms

• preinvasion
  adjective
• reinvasion
  noun

Etymology

Origin of invasion

1400–50; late Middle English < Late Latin invāsīon- (stem of invāsiō ), equivalent to invās ( us ), past participle of invādere + -iōn- -ion; see invade

Explanation

An invasion is the movement of an army into a region, usually in a hostile attack that's part of a war or conflict. World history is full of descriptions of invasions. One country's army plundering or taking over a city or piece of land in another country is an invasion. You can call other mass movements invasions as well, like a horrifying invasion of your kitchen by cockroaches, or the invasion of a stadium by excited soccer fans. A common phrase is "invasion of privacy," which means an unfair intrusion into someone's personal space or private information.

Example Sentences

Ukrainian sea drones have revolutionised naval warfare since Moscow's invasion, relentlessly hunting down Russian warships and tankers in the open sea and even at naval bases.

From BBC • May 8, 2026

Magazine depth refers to the munitions stockpiles the U.S. maintains, which have been a staple in headlines since the Russian invasion of Ukraine in 2022.

From Salon • May 8, 2026

A massive invasion force that Xerxes has led against Greece has just been destroyed; we watch as news of the disaster arrives, followed by the bedraggled monarch himself.

From The Wall Street Journal • May 6, 2026

In 1991, the network gave Americans a live and uninterrupted look at the invasion of Iraq.

From Los Angeles Times • May 6, 2026

With Duke Valentino as his instrument and the French invasion as his opportunity, he achieved all those things that I discussed earlier in describing the actions of the Duke.

From "The Prince" by Niccolò Machiavelli

Related Words

• aggression
• assault
• breach
• incursion
• infiltration
• infringement
• intrusion
• offensive
• onslaught
• raid
• violation