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

bucky bits
 /buh'kee bits/, n.

    1. [obs.] The bits produced by the CONTROL and META shift keys on a SAIL
    keyboard (octal 200 and 400 respectively), resulting in a 9-bit keyboard
    character set. The MIT AI TV (Knight) keyboards extended this with TOP and
    separate left and right CONTROL and META keys, resulting in a 12-bit
    character set; later, LISP Machines added such keys as SUPER, HYPER, and
    GREEK (see space-cadet keyboard).

    2. By extension, bits associated with ?extra? shift keys on any keyboard,
    e.g., the ALT on an IBM PC or command and option keys on a Macintosh.

    It has long been rumored that bucky bits were named for Buckminster Fuller
    during a period when he was consulting at Stanford. Actually, bucky bits
    were invented by Niklaus Wirth when he was at Stanford in 1964--65; he
    first suggested the idea of an EDIT key to set the 8th bit of an otherwise
    7-bit ASCII character). It seems that, unknown to Wirth, certain Stanford
    hackers had privately nicknamed him ?Bucky? after a prominent portion of
    his dental anatomy, and this nickname transferred to the bit. Bucky-bit
    commands were used in a number of editors written at Stanford, including
    most notably TV-EDIT and NLS.

    The term spread to MIT and CMU early and is now in general use. Ironically,
    Wirth himself remained unaware of its derivation for nearly 30 years, until
    GLS dug up this history in early 1993! See double bucky, quadruple bucky
    .


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

bucky bits

   /buh'kee bits/ 1. Obsolete.  The bits produced by the CONTROL
   and META shift keys on a SAIL keyboard (octal 200 and 400
   respectively), resulting in a 9-bit keyboard character set.
   The MIT AI TV (Knight) keyboards extended this with TOP and
   separate left and right CONTROL and META keys, resulting in a
   12-bit character set; later, LISP Machines added such keys as
   SUPER, HYPER, and GREEK (see space-cadet keyboard).

   2. By extension, bits associated with "extra" shift keys on
   any keyboard, e.g.  the ALT on an IBM PC or command and option
   keys on a Macintosh.

   It has long been rumored that "bucky bits" were named after
   Buckminster Fuller during a period when he was consulting at
   Stanford.  Actually, bucky bits were invented by Niklaus Wirth
   when *he* was at Stanford in 1964--65; he first suggested the
   idea of an EDIT key to set the 8th bit of an otherwise 7 bit
   ASCII character.  It seems that, unknown to Wirth, certain
   Stanford hackers had privately nicknamed him "Bucky" after a
   prominent portion of his dental anatomy, and this nickname
   transferred to the bit.  Bucky-bit commands were used in a
   number of editors written at Stanford, including most notably
   TV-EDIT and NLS.

   The term spread to MIT and CMU early and is now in general
   use.  Ironically, Wirth himself remained unaware of its
   derivation for nearly 30 years, until GLS dug up this
   history in early 1993!  See double bucky, quadruple bucky.

   (2001-06-22)