"Region" is a general term in the WoW UI for a type of frame that can hold content. On this page, however, "Region" will refer specifically to the base frame of any Aura. For the most part WeakAuras provides settings in its config for changes you might want to make to Aura regions or their child frames, but advanced users can tweak additional settings or change things dynamically through custom code. It should be noted that doing so is moving out of "supported" uses of WeakAuras, so there can be