Metastasis
Etymology
From Greek "metastasis" (a removing, a change of place), from "meta" (change) and "stasis" (a standing, placement) — literally "a change of standing." Medicine borrowed it for cells that break away and re-establish themselves in new tissue.
noun · /muh-TAS-tuh-sis/
The spread of a disease, especially cancer, from its original site to other parts of the body.
What it names
The clinical name for cancer’s spread — and a sharp metaphor for any harm that migrates and takes root elsewhere.
Example
By the time it was found, the tumor had already begun its metastasis to the liver.
Related idea
Metastasis is the spreading of disease to new sites; a relapse is its return to the same place after apparent recovery — spread outward versus coming back.