What is Hysteresis?

The simpliest way to describe hysteresis is by example. When you press down on an object such as memory foam pillow and it slowly returns to its prior state this is an example hysteresis. There is a lag in the response time for the object to return to is former state. If you press and object and it does not spring back or return to its former shape then it does not fall in this category. The pressing down on the object is the change in the objects original structure. In the case of hysteresis an objects reaction is predictible.