intrusion

American  

[in-troo-zhuhn] / ɪnˈtru ʒən /

noun

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

• intrusional adjective

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

Example Sentences

Johnny Crocker, Franklin County’s sheriff, is among opponents who say the prison is an example of government intrusion and waste.

From The Wall Street Journal • Mar. 24, 2026

Medical-device maker Stryker saw a significant intrusion this past week that erased many devices on its network.

From Barron's • Mar. 13, 2026

Bringing Keller and Knight onstage somewhat sweetened the awkward position in which the show placed Storrie, but it doesn’t entirely ameliorate the White House’s intrusion into both hockey teams’ Olympic glory.

From Salon • Mar. 6, 2026

He is a constraint disruption to your life, and even when there is silence, you are waiting for the next intrusion.

From MarketWatch • Mar. 3, 2026

Ansley was part of an aristocracy that brooked no intrusion, at least not now, Ben thought.

From "The Great Santini" by Pat Conroy

Related Words

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