DuckCorp Dico

Found one definition

1.                 From The Jargon File (version 4.4.7, 29 Dec 2003):
                   
   
   
                   
                     
   thud
    n.
       1. Yet another metasyntactic variable (see foo). It is reported that at
       CMU from the mid-1970s the canonical series of these was ‘foo’, ‘bar’,
       ‘thud’, ‘blat’.
       2. Rare term for the hash character, ‘#’ (ASCII 0100011). See ASCII for
       other synonyms.