A stimulus is anything that can trigger a physical or behavioral change. The plural of stimulus is stimuli.
Stimuli can be external or internal.
An example of external stimuli:
- Your body responding to a medicine
An example of internal stimuli:
- Your vital signs changing due to a change in the body
- Temperature changes
Taber's Cyclopedic Medical Dictionary, 23rd ed. F.A. Davis Company; 2017. www.tabers.com/tabersonline/. Accessed January 26, 2017.