V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

BNF
       Backus-Naur Form (TTCN, ...)


The Jargon File (version 4.4.7, 29 Dec 2003):

BNF
 /B?N?F/, n.

    1. [techspeak] Acronym for Backus Normal Form (later retronymed to
    Backus-Naur Form because BNF was not in fact a normal form), a
    metasyntactic notation used to specify the syntax of programming languages,
    command sets, and the like. Widely used for language descriptions but
    seldom documented anywhere, so that it must usually be learned by osmosis
    from other hackers. Consider this BNF for a U.S. postal address:


      ::=   

      ::=  |  "."

      ::=   [] 
                   |  

      ::= []   

      ::=  ","   

    This translates into English as: ?A postal-address consists of a name-part,
    followed by a street-address part, followed by a zip-code part. A
    personal-part consists of either a first name or an initial followed by a
    dot. A name-part consists of either: a personal-part followed by a last
    name followed by an optional jr-part (Jr., Sr., or dynastic number) and
    end-of-line, or a personal part followed by a name part (this rule
    illustrates the use of recursion in BNFs, covering the case of people who
    use multiple first and middle names and/or initials). A street address
    consists of an optional apartment specifier, followed by a street number,
    followed by a street name. A zip-part consists of a town-name, followed by
    a comma, followed by a state code, followed by a ZIP-code followed by an
    end-of-line.? Note that many things (such as the format of a personal-part,
    apartment specifier, or ZIP-code) are left unspecified. These are presumed
    to be obvious from context or detailed somewhere nearby. See also parse.

    2. Any of a number of variants and extensions of BNF proper, possibly
    containing some or all of the regexp wildcards such as * or +. In fact
    the example above isn't the pure form invented for the Algol-60 report; it
    uses [], which was introduced a few years later in IBM's PL/I definition
    but is now universally recognized.

    3. In science-fiction fandom, a ?Big-Name Fan? (someone famous or
    notorious). Years ago a fan started handing out black-on-green BNF buttons
    at SF conventions; this confused the hacker contingent terribly.


The Free On-line Dictionary of Computing (30 December 2018):

BNF

   Backus-Naur Form.  Originally Backus Normal Form.

   [Jargon File]