Pronunciation: (mu-tas'tu-sis),[key] —n., —pl.-sesPronunciation: (-sēz").[key] 1. Pathol. a. the transference of disease-producing organisms or of malignant or cancerous cells to other parts of the body by way of the blood or lymphatic vessels or membranous surfaces.
b. the condition produced by this.
2. transformation (def. 3).
3. Rhet.a rapid transition, as from one subject to another.
4. Physics.a change in position or orbit of an elementary particle.