Anis,
For the purpose of the PMP Exam: Scope Creep is defined as:
Adding features and functionality (project scope) without addressing the effects on time, costs, and resources, or without customer approval.
Outside of the PMP exam I have never heard the term used in regards to removing scope. I suppose this is mainly so because removing scope in an uncontrolled fashion is usually not a big problem. But adding scope in such a way is.
However, your question is an interesting one to ponder. But for the PMP exam you should not worry about it.