TOPIC: Work packages VS Define activites

Hi All,
looking for another understanding on Work packages ( which is lowest package of WBS ) and activity . Work package is not a activity ? or it is group of activity ? Kindly help.

Thanks

PMBOK page 181 stated the key benefit for Define Activities process is that "it decomposes work packages into schedule activities...", therefore, it is a series of activities to complete the work package. For example, you have a work package called "Chapter 5 Project Scope Management Exam Readiness" and the activities are:
1. Listen to PrepCast for section 5.1 to 5.6
2. Read PMBOK for section 5.1 to 5.6
3. Do exam questions for Chapter 5
4. Revise incorrect questions

Hope this explanation helps.