1. Method of application of a therapeutic agent to produce changes to biological tissue (i.e., thermal, acoustic, light, mechanical, cold packs, or electric appliances). 2. Homeopathic term for a condition that modifies drug action. 3. Specific sensory entity such as taste or vision. 4. Form of imaging such as x-ray, fluoroscopy, ultrasound, nuclear medicine, duplex Doppler, computed tomography (CT), and magnetic resonance imaging (MRI).