metastasis

metastasis 1 The spread of cancerous cells from one part of the body to another. The cells may be carried by the lymphatic system or in the blood. Cells that have metastasized are like those in the original (primary) tumor. For example, if the cancer begins in the stomach and spreads to the lung, the cancer cells in the lung are metastatic stomach cancer cells. 2 A collection of tumor cells that has spread. The plural of metastasis is metastases.