Pronunciation: (in-trOO'zhun),[key] —n. 1. an act or instance of intruding.
2. the state of being intruded.
3. Law. a. an illegal act of entering, seizing, or taking possession of another's property.
b. a wrongful entry after the determination of a particular estate, made before the remainderman or reversioner has entered.
4. Geol. a. emplacement of molten rock in preexisting rock.
b. plutonic rock emplaced in this manner.
c. a process analogous to magmatic intrusion, as the injection of a plug of salt into sedimentary rocks.
d. the matter forced in.