On a daily basis, I hear managers, directors, and executives referring to the MS Project file as "the project plan". I must frustrate a lot of people because I refuse to call it that. I refer to it as the activity list and Gantt Chart. Some PMPs call Gantt charts "bar charts" but I am one of those people who still calls a cotton swab a Q-Tip. Either way, if you refer to the MS Project file as an activity list and bar chart, you're on the path to passing the PMI exam. If you're still convinced it's a project management plan, I can almost guarantee you're not going to pass. A project management plan, as defined in the in the Project Management Body of Knowledge (PMBOK) is "A formal, approved document that defines how the project is executed, monitored, and controlled. It may be summary or detailed and may be composed of one or more subsidiary management plans and other planning documents.
I usually refer to my "plans" as a project management packet. I include my signed charter, the communications plan, risk plan, resource plan... I keep them in a central packet and also a central virtual folder for easy access.
And that's all I have to say about that.