1.(Theol.) A spiritual change, as during baptism.
2.(Med.) A change in the location of a disease, as from one part to another.
3.Especially: The migration of cancerous or malignant cells from the site of their origin to other parts of the body. Such cells may migrate to multiple new locations, making therapy more difficult and often leading to death.
4.(Physiol.) The act or process by which matter is taken up by cells or tissues and is transformed into other matter; in plants, the act or process by which are produced all of those chemical changes in the constituents of the plant which are not accompanied by a production of organic matter; metabolism.