Source : Free On-Line Dictionary of Computing

TDF
     
         An {intermediate language}, a close relative of
        {ANDF}.  A TDF program is an {ASCII} stream describing an
        {abstract syntax tree}.
     
        TDF became part of {TenDRA} in abut 2001.
     
        ["TDF Specification", Defence Research Agency/Electronics
        Division, Great Malvern, England, +44 684 895314].
     
        (2003-05-13)