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.

---

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

---

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

---

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

In a BBC interview before he was asked to take the post, he made clear he opposes the limitation of MPs' terms as an intrusion on the right of voters to freely choose their representatives.

From BBC ● Aug. 11, 2026

The toy and game maker discovered the intrusion in late March.

From The Wall Street Journal ● Aug. 3, 2026

The intrusion was first detected by Hugging Face last week, when it noticed tens of thousands of AIs nipping at its system.

From Los Angeles Times ● Jul. 29, 2026

After it detected the intrusion, Hugging Face tried using Anthropic models—including Fable 5 and its earlier Opus model—to analyze its logs.

From The Wall Street Journal ● Jul. 24, 2026

He was ringing down the curtain on an orangutan when the business of the King’s health made its ultimate intrusion.

From "The Princess Bride" by William Goldman

"What else were they up to? What were the other intrusions?"

From BBC ● Jul. 30, 2026

The horizontal layering allows some seismic waves to travel long distances, while the vertical intrusions appear to disrupt and weaken others.

From Science Daily ● Jul. 18, 2026

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

From Los Angeles Times ● Jun. 16, 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

Such intrusions are so common that Border Patrol agents advise ranchers to leave water and food outside, beside their doors.

From "Enrique's Journey" by Sonia Nazario

Related Words

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