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

One property manager said a building has experienced what she called “large-scale intrusion events.”

From Los Angeles Times ● Oct. 2, 2026

It later called the intrusion a “marketing campaign” and said it wouldn’t publish the stolen data.

From Slate ● Sep. 30, 2026

The researchers identified a large thermal gradient, with temperatures reaching approximately 350 degrees Celsius beside the magma intrusion and falling to about 72 degrees Celsius at an ancient seafloor asphalt spill roughly 300 meters higher.

From Science Daily ● Sep. 26, 2026

It will be a constant intrusion in your life.

From MarketWatch ● Sep. 21, 2026

The class went back and forth like that day after day, and when the bell rang it was always a surprise and an intrusion.

From "Drama High" by Michael Sokolove

After reports of the first bank breaches emerged, Artex updated its user guidelines to specify that the tool must not be used for unauthorized intrusions, data theft or other malicious reasons.

From The Wall Street Journal ● Oct. 6, 2026

Greaney said blame rested with Travelodge as an organisation rather than with individual staff, and a culture had developed in which room intrusions were regarded as "one of those things".

From BBC ● Oct. 1, 2026

The new hack joins a long list of recent disclosures by leading technology companies and researchers alike of cyber intrusions aided by fast-evolving artificial-intelligence tools.

From The Wall Street Journal ● Sep. 18, 2026

I couldn’t hear them at all, but I got the impression that those intrusions and distractions were weighing on her.

From Los Angeles Times ● Jul. 22, 2026

The gnats were too frantic to notice these intrusions, however, and since every pebble missed its final mark, the toad continued to squat and grimace without so much as a twitch.

From "Tuck Everlasting" by Natalie Babbit

Related Words

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