This is exactly why the acronym for display standards was so terrible.

The Extended Graphics Adapter (abbreviated XGA, obviously) by IBM was introduced with multiple resolutions available, named XGA and various deritives.

EGA came earlier and was colloquially used to refer to 16-color display modes, but wasn’t used to define a specific resolution.

More specifically, EGA was a color palatte that had 64 colors available, 16 of which could be displayed at one time.

And then there’s CGA which came prior to EGA, but like it referred to color modes rather than resolution.