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

After all, people aren’t as busy, so they won’t mind the intrusion, right?

From The Wall Street Journal • Jun. 12, 2026

Gregory Jones KC, for Vale of Glamorgan council, called the proposal "a logical rounding off of Llantwit Major rather than an intrusion into untouched landscape".

From BBC • Jun. 11, 2026

Nunez promised "a strong law enforcement response" during the players' return celebrations and fines for "obstructing traffic" in the event of any intrusion onto the Paris ring road.

From Barron's • May 31, 2026

It simply makes intrusion easier to normalize because machines rather than officers perform the searching.

From Slate • May 20, 2026

He stood tongue-tied, feeling his very existence an intrusion, while Zau directed Heqet to the farthest stall, and to the cupboard where he would find the stake.

From "The Golden Goblet" by Eloise Jarvis McGraw

Related Words

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