|1.||the act or an instance of intruding; an unwelcome visit, interjection, etc: an intrusion on one's privacy|
|2.||a. the movement of magma from within the earth's crust into spaces in the overlying strata to form igneous rock|
|b. 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 (ĭn-tr'zhən) Pronunciation Key
The movement of magma through cracks in underground rocks within the Earth, usually in an upward direction. ◇ 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. Compare extrusion.