VRML - (Virtual Reality Mark up Language) - (Pronounced "ver-mal") - (Note, X3D has succeeded VRML) - VRML was a specification for displaying 3-dimensional objects on the World Wide Web. It's often considered the 3-D equivalent of HTML. Files written in VRML have a .wrl extension (short for world). To view these files, you need a VRML browser or a VRML plug-in to your web browser.