- The act or process of entering or intruding.
- ingression of the sea onto land
- (metaphysics) The process by which a potentiality enters into actuality.
1967, Whitehead's Metaphysics, Edward Pols, page 164:
- […] it is by virtue of the individual essence that an eternal object remains precisely the same eternal object through all its ingressions […]
- (biology) The inward migration of cells from the blastula during gastrulation.
1940, Libbie Henrietta Hyman, The Invertebrates, page 496:
- Ingression of ectodermal cells from the area between the velar lobes establishes the cerebral ganglia and similar ingressions produce the other ganglia.