Source : Free On-Line Dictionary of Computing

Basic Language for Implementation of System Software
     
         (BLISS, or allegedly, "System Software
        Implementation Language, Backwards") A language designed by
        W.A. Wulf at {CMU} around 1969.
     
        BLISS is an {expression language}.  It is {block-structured},
        and typeless, with {exception handling} facilities,
        {coroutines}, a {macro} system, and a highly {optimising
        compiler}.  It was one of the first non-{assembly languages}
        for {operating system} implementation.  It gained fame for its
        lack of a {goto} and also lacks implicit {dereferencing}: all
        symbols stand for addresses, not values.
     
        Another characteristic (and possible explanation for the
        backward acronym) was that BLISS fairly uniformly used
        backward {keywords} for closing blocks, a famous example being
        ELUDOM to close a MODULE.  An exception was BEGIN...END though
        you could use (...) instead.
     
        DEC introduced the NOVALUE keyword in their dialects to allow
        statements to not return a value.
     
        Versions: CMU {BLISS-10} for the PDP-10; CMU {BLISS-11},
        {BLISS-16}, DEC {BLISS-16C}, DEC {BLISS-32}, {BLISS-36} for
        {VAX}/{VMS}, {BLISS-36C}.
     
        ["BLISS: A Language for Systems Programming", CACM
        14(12):780-790, Dec 1971].
     
        [Did the B stand for "Better"?]
     
        (1997-03-01)