Forget what you read on Wikipedia or saw on Grease Lightning. You don't live in an encyclopedia bounded by definitions, and you're not trying to be real life cosplays -- hopefully. You are a millenial and grounded in reality.

The pompadour is generally characterized by tightly held-down sides with a large volume on the top that gradually recedes as you move towards the back. The sides are usually slicked-back, tapered, or faded. The pomp (middle section) is crafted to have volume and forwardness. In a way, it should appear confident and have flow. The part(s) is optional. You can see examples of the two types above.

I provided a general definition because it's important to understand AND accept that the definition of a pompadour will evolve over time. These characteristics are really the only two things that remain constant in each variation. Everything changes over time, and the concept of the pompadour is no exception. As you can see below, here is a loose and finger-combed rendition of the pompadour. It has its own unique set of aesthetics.