safari for Mac
Does safari for mac have the same small window display function as iPhone and iPad? I mean this button in the picture. If I call it incorrectly, please let me know.
MacBook Pro
It's called Picture-in-Picture (PiP), and it's avaliable for certain websites (like YouTube, etc), but generally only while on the website.
Should you want to watch a video with a media player such as QuickTime, etc. on your Mac, you can simply resize and drag the window to where you want it.