Can you tell me the differencebetween Adware and Spyware?

maybe like this, adware is adverstising application, just like when we using an application there is an advers upper of the program, usually I call that adware, but spyware is more use like a thief, this spyware watch our habbit, see our cookies and psswd, and then report to the spyware owner, so they know many about our important data.