What is the difference between a herbivore a carnivore and a scavenger?

A carnivore is mainly known as a 'meat eater'. Exmaple: Lion. Then you have scavengers, which'll basically eat anything they find. Such as a rat. :O So I guess that means the carnivores are predatores, and the scavengers just find dead animals and eat them, they don't kill. Hope that helped. :]