Noun

(en noun)

The forcible inclusion or entry of an external group or individual; the act of intruding.

* He viewed sales calls as an unwelcome intrusion .

*{{quote-magazine, date=2012-12-14

, author=Simon Jenkins, authorlink=Simon Jenkins , title=We mustn't overreact to North Korea boys' toys , volume=188, issue=2, page=23 , date=2012-12-21 , magazine= citation , passage=The threat of terrorism to the British lies in the overreaction to it of British governments. Each one in turn clicks up the ratchet of surveillance, intrusion and security. Each one diminishes liberty.}}

(geology) Magma forced into other rock formations; the rock formed when such magma solidifies.

Noun

(en noun)

The act or process of entering or intruding

ingression of the sea onto land

(metaphysics) The process by which a potentiality enters into actuality

*{{quote-book, 1967, Whitehead's Metaphysics, Edward Pols citation

, passage=

(biology) The inward migration of cells from the blastula during gastrulation

*{{quote-book, 1940, Libbie Henrietta Hyman, The Invertebrates, page=496

, passage=Ingression' of ectodermal cells from the area between the velar lobes establishes the cerebral ganglia and similar ' ingressions produce the other ganglia. }}