Source : Free On-Line Dictionary of Computing

three-letter acronym
     
        (TLA) The canonical self-describing abbreviation for the name
        of a species with which computing terminology is infested.
        Examples include {MCA}, {FTP}, {SNA}, {CPU}, {MMU}, {DMU},
        {FPU}, {TLA}.  For a complete list of the TLAs in this
        dictionary, see {TLAs}.
     
        Sometimes used by extension for any confusing acronym.  People
        who like this looser usage argue that not all TLAs have three
        letters, just as not all four-letter words have four letters.
        One also hears of "ETLA" (Extended Three-Letter Acronym) being
        used to describe four-letter acronyms.  The term "SFLA"
        (Stupid Four-Letter Acronym) has also been reported.
     
        See also {YABA}.
     
        The self-effacing phrase "TDM TLA" (Too Damn Many...) is often
        used to bemoan the plethora of TLAs in use.  In 1989, a random
        of the journalistic persuasion asked hacker Paul Boutin "What
        do you think will be the biggest problem in computing in the
        90s?"  Paul's straight-faced response: "There are only 17,000
        three-letter acronyms." (To be exact, there are 26^3 =
        17,576.)
     
        (1994-12-14)