What does the word stimulus mean?

Answer 1

A stimulus is basically considered to be a detectable change inside or outside the body. If you sit quietly for a while, and then a loud noise goes off, that is a change from the quiet state, and therefore considered a stimulus. You most likely will jump.

But if you get used to that loud noise, then you have adapted to it and it no longer triggers a response, it is no longer a stimulus; it is not changing.

Basically something which urges a response is called a stimulus.

Answer 2

A stimulus is something that causes a response or reaction in an organism or system. It can be any sort of signal or input that provokes an action or change in behavior.