What is another word for an extinct volcano?

Dormant, which is probably more accurate as being the opposite of Active, then saying Inactive, which only means not active, and if it's NOT active, it must be something other then Active, of course when looking to the Physical Laws, there is the law of Motion, which reads "Everything is in a Constant state of Motion, Even when appearing to be at Rest" So, as Active, is to Action, and Action is to Motion, perhaps there is no such a thing as Dormant, or Inactive to begin or end with. But Dormant should do for now if that was the Word you were looking for.