Powerhead or wave maker?

[Dragon780]

Hi guys, this might sound stupid of me to ask, but i rather get it clear.
so it would be great if someone could clearify this for me.
what is a powerhead and what is a wavemaker?
can there be something that is used as a wave maker and powerhead?
i read and heard that a powerhead is used to create water flow, but isn't a wave maker also used for that purpose?
and what is the vortech mp 40 then? is that a wave maker or a powerhead?
And is a powerhead recommended or needed, or is a wavemaker needed?

thanks everyone