What is the definition of applied science?

Applied science is using your scientific knowledge and applying it to practical situations. For e.g. experiments, technology, inventions etc.

if you don't get that, think about it like PE. It's like using the sport knowledge (i.e. components of fitness and training, health, nutrition etc) and applying it in practical situations. For e.g. playing sports like Football, Cricket, Rugby etc

Hope this helps!