stimuli

noun

1. 1

   Any external phenomenon that has an influence on a system, by triggering or modifying an internal phenomenon.

   “an economic stimulus”

2. 2

   Something external that elicits or influences a physiological or psychological activity or response.

3. 3

   Anything effectively impinging upon any of the sensory apparatuses of a living organism, including physical phenomena both internal and external to the body.

4. 4

   Anything that induces a person to take action.