Stands for "Virtual Reality Modeling Language."
VRML is a modeling language designed to deliver interactive 3D scenes over the World Wide Web. VRML files are similar to HTML files, which use text and markup language to build a webpage. VRML files use text and markup language to create a 3D scene (or "world") and the objects within it, define how the user interacts with it, and make hyperlinks to other worlds. A web user can view VRML worlds through a dedicated VRML browser or a web browser using a VRML plug-in.
A VRML file (with a .wrl file extension) is a plain text file that defines the scene and objects within it using a standard markup language. 3D objects are created by specifying individual points along the X, Y, and Z axes, then connecting them to create a wireframe, and finally using those wireframes to create surfaces and apply textures. VRML worlds can also include animation, sounds, lights, and interactive elements. The language is simple enough that someone with a sufficient understanding of 3D graphics can write a VRML file in a plain text editor.
The first version of the VRML specification was released in 1994, supporting static 3D worlds. A second version, VRML97, was released in 1997, adding support for animation and interaction through a scripting language. The format never found a large audience due to the limited bandwidth of dial-up Internet that most people used at the time. An XML-based successor language, X3D, was released in 2001.