Metastasis (thing)

1. The spread of a disease from one organ or body part to another which is not directly connected to the first.
   
   
2. The spread of cancer from its original site to another part of the body; this happens because cancer cells break off the original tumor and spread via the blood or lymph system.

From the BioTech Dictionary at http://biotech.icmb.utexas.edu/. For further information see the BioTech homenode.