From LQWiki

gvim is a simple way to invoke a GUI version of the vim editor. In nearly all installations, gvim is simply a symlink to the vim binary, which checks the name by which it was invoked to determine which functionality to use. Running gvim is exactly the same as running the vim binary with the "-g" option.

The GUI form of Vim supports several different toolkits, including: GTK, GTK2, Motif, Athena, Carbon, and Photon.