Much like the term WYSIWYG, WYSIWYE describes a type of integrated editing GUI. The term stands for "What You See is Where You Edit," in reference to an integrated editing interface. Such as an admin panel in a website fully integrated into the homepage.
Jim: "Man, this CMS is lame, I have to click the admin panel, then login, then have no clue what I'm editing because I can't see it update due to the fact I'm in another page."
Tom: "You need to code a WYSIWYE interface"