Mac OS
Mac OS, often known as just Mac, is Apple's flagship operating system, first released on March 24th, 2001. It is based on Berkeley Unix and known for its ease of use and high price tag. It's like having a nice car - it's great, but expensive!
Version 10.0 of the software, known as OSX, lasted an abnormally long amount of time which led to "OSX" often being used to refer to Mac OS as a whole - which worked until Mac OS 11 released in 2020. Current names are also codenamed after placed in California. As of April 3rd, 2025, the current version is Mac OS 15 "Sequoia".
Compatible Software
Due to the aforementioned roots in Unix, compatibility between Mac and Linux software is more likely than between Mac and Windows (but not guaranteed).
The Adobe creative suite (Premiere, After Effects, etc) as well as Final Cut Pro (Apple's flagship video editor) are the two most popular video editors on Mac. Vegas, however, does not.
Emulation
Infinite Mac[1] is a great place to get started with Mac Emulation, going up to OSX 10.4 "Tiger". It has support for virtual hard drives and disk images which can allow you to use old software, and transfer work between the host and emulated machines.