Source : Free On-Line Dictionary of Computing

Compiled HTML
     
         A {Microsoft} file format for
        distributing a collection of {HTML} files, along with their
        associated images, sounds, etc., as a single compressed
        archive file.
     
        Microsoft use this format for {Windows} {HTML Help} files.
        Most chms include a project (.hhp) file listing the included
        files and basic settings, a contents (.hhc) file, an index
        (.hhk) file, html files, and, optionally, image files.
     
        Users view chms with hh.exe, the HTML Help viewer installed
        with {Internet Explorer}.
     
        Filename extension: .chm.
     
       
     {(http://msdn.microsoft.com/library/en-us/htmlhelp/html/vsconHH1Start.asp)}.
     
        (2003-05-17)