Source : Free On-Line Dictionary of Computing

Tagged Image File Format
     
         (TIFF) A {file format} used for
        still-image {bitmaps}, stored in tagged fields.  {Application
        programs} can use the tags to accept or ignore fields,
        depending on their capabilities.
     
        While TIFF was designed to be extensible, it lacked a core of
        useful functionality, so that most useful functions (e.g.
        {lossless} 24-bit colour) requires nonstandard, often
        redundant, extensions.  The incompatibility of extensions has
        led some to expand "TIFF" as "Thousands of Incompatible File
        Formats".
     
        Compare {GIF}, {PNG}, {JPEG}.
     
        (1997-10-11)