What do the terms EGD/XGD refer to?

Here are two articles describing Environmental Graphic Design and Experiential Graphic Design.In 2014 SEGD changed the "E" from Environmental to Experiential. This was done to recognize the rapid expansion over the last decade of the scope of what this profession does. Experiential encompasses all of Environmental Graphic Design, but expands it to include digital technologies, content (such as video, images and stories) and most importantly the notion of interaction.

From an educators perspective the article Towards an Experiential Futureby Justin Molloy provides a very good perspective of how the profession is evolving.

Finally, here is a link to the SEGD presentation, What is Experiential Graphic Designwhich works really well for faculty and career counselors who would like to show students interested in this field the sort of design work it covers.