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.