intrusion

American  

[in-troo-zhuhn] / ɪnˈtru ʒən /

noun

• intrusions
  plural

1. an act or instance of intruding.

2. the state of being intruded.

3. Law.

   1. an illegal act of entering, seizing, or taking possession of another's property.

   2. a wrongful entry after the determination of a particular estate, made before the remainderman or reversioner has entered.

4. Geology.

   1. emplacement of molten rock in preexisting rock.

   2. plutonic rock emplaced in this manner.

   3. a process analogous to magmatic intrusion, as the injection of a plug of salt into sedimentary rocks.

   4. the matter forced in.

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intrusion British  

/ ɪnˈtruːʒən /

noun

1. the act or an instance of intruding; an unwelcome visit, interjection, etc

   an intrusion on one's privacy

2. 1. the movement of magma from within the earth's crust into spaces in the overlying strata to form igneous rock

   2. any igneous rock formed in this way

3. property law an unlawful entry onto land by a stranger after determination of a particular estate of freehold and before the remainderman or reversioner has made entry

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intrusion Scientific  

/ ĭn-tro̅o̅′zhən /

1. The movement of magma through cracks in underground rocks within the Earth, usually in an upward direction.

2. ◆ Rocks that form from the underground cooling of magma are generally coarse-grained (because they cool slowly so that large crystals have time to grow) and are called intrusive rocks.

3. Compare extrusion

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Other Word Forms

Derived Forms

• intrusional
  adjective

Inflected Forms

Nouns

• intrusions
  plural

Etymology

Origin of intrusion

1250–1300; Middle English < Medieval Latin intrūsiōn- (stem of intrūsiō ), equivalent to Latin intrūs ( us ), past participle of intrūdere to intrude (equivalent to intrūd- verb stem + -tus past participle suffix, with dt < s ) + -iōn- -ion

Explanation

An intrusion is a deliberate move into someone else's territory — either literal or figurative. When your sister interrupts your conversation with that girl from math class, that's an intrusion. If someone breaks into your home, that's also an intrusion. First used in the late 14th century, the noun intrusion derives from the Latin word intrudere, which combines the prefix in-, meaning "in," and trudere, meaning "to thrust, push." If someone reads your diary, that's considered an intrusion of privacy. Ordering a Muslim woman to take off her veil would be considered an intrusion on religious beliefs. You may remember intrusion used in science class to describe molten rock that forms in an earlier rock formation.

Example Sentences

See Examples For:

intrusion intrusions

“Certainly some of those homes will have some type of vapor intrusion risk, really the only way to know for sure is to go test the home,” he said.

From Los Angeles Times ● Aug. 11, 2026

Hugging Face on July 16 announced that it had detected and contained the intrusion and reported it to law enforcement—five days before OpenAI announced it had connected the activity to its own internal testing.

From The Wall Street Journal ● Aug. 4, 2026

Hugging Face had reported the cyber "intrusion" last week, without mentioning OpenAI.

From Barron's ● Jul. 22, 2026

Last year, the publisher of the Sun newspaper agreed to pay "substantial damages" and apologised to the duke to settle a long-running legal battle over claims of unlawful intrusion into his life.

From BBC ● Jul. 7, 2026

This new-comer would not welcome intrusion, I felt certain of that.

From "Rebecca" by Daphne du Maurier

He's challenged what he sees as damaging press intrusions that have harmed his private life and his relationships.

From BBC ● Jul. 7, 2026

For some soccer fans, though, the commercial breaks are an intrusions.

From Los Angeles Times ● Jun. 16, 2026

These underground intrusions are important because they help build and reshape volcanic islands over time.

From Science Daily ● May 14, 2026

She said Latvia's anti-drone systems had not been deployed quickly enough to counter the drone intrusions.

From Barron's ● May 14, 2026

Granite intrusions poked above the water and formed a sort of breakwater that defended the island from some of the worst of the new storms.

From "Ship Breaker" by Paolo Bacigalupi

Related Words

• encroachment
• imposition
• incursion
• interference
• intervention
• invasion