Two video terms: Variable Refresh Rate and Low Framerate Compensation (adjusting the refresh rate for the framerate of a slower video source). Both pertain mostly in gaming and entertainment software.

CUA is Common User Access, which just means standards such as universally implementing Ctrl-C and Ctrl-V for copy/paste in apps. Linux devs do tend to follow common conventions, they just aren't as strictly enforced as when a corporation has near-total control over the software.