See frame for additional meanings.
In creating a Web site, frames is the use of multiple, independently controllable sections on a Web presentation. This effect is achieved by building each section as a separate HTML file and having one "master" HTML file identify all of the sections. When a user requests a Web page that uses frames, the address requested is actually that of the "master" file that defines the frames; the result of the request is that multiple HTML files are returned, one for each visual section. Links in one frame can request another file that will appear in another (or the same) frame. A typical use of frames is to have one frame containing a selection menu in one frame and another frame that contains the space where the selected (linked to) files will appear.
Frames, originally created by Netscape as an HTML extension and now part of the HTML 4.0, specification are defined with HTML FRAMESET and FRAME tags. Sites that use frames need to create an alternative scheme of pages for requests from browsers that don't support them and possibly for users that prefer a non-frames version.