What is Activity?

Activity in PMP is defined as:

• must be performed to produce the project's deliverables.
• is usually defined at the work package level.

Work Packages or Tasks are:

• activities that can be broken down into tasks by the work package owner.
  

An Activity:

• is an element of project work that requires action to produce a deliverable.
• shares some common characteristics such as expected duration, budget and resources.