The Collaborative International Dictionary of English v.0.48:

Meta- \Met"a-\, Met- \Met-\ [Gr. meta` between, with, after;
   akin to AS. mid with, G. mit, Goth. mi[thorn], E. mid, in
   midwife.]
   1. A prefix meaning between, with, after, behind, over,
      about, reversely; as, metachronism, the error of placing
      after the correct time; metaphor, lit., a carrying over;
      metathesis, a placing reversely.
      [1913 Webster]

   2. (Chem.) A prefix denoting:
      (a) Other; duplicate, corresponding to; resembling; hence,
          metameric; as, meta-arabinic, metaldehyde.
      (b) (Organic Chem.) That two replacing radicals, in the
          benzene nucleus, occupy the relative positions of 1
          and 3, 2 and 4, 3 and 5, 4 and 6, 5 and 1, or 6 and 2;
          as, metacresol, etc. See Ortho-, and Para-.
      (c) (Inorganic Chem.) Having less than the highest number
          of hydroxyl groups; -- said of acids; as,
          metaphosphoric acid. Also used adjectively.
          [1913 Webster]

   3. A prefix meaning at a level above, as in metaphysics,
      metalanguage.
      [PJC]

The Free On-line Dictionary of Computing (19 January 2023):

META

    The assembly language for the CYBER 200,
   developed at CDC ca 1977.

   [CDC Pub 60256020].

   [Jargon File]

   (1994-11-16)


The Free On-line Dictionary of Computing (19 January 2023):

meta

    /me't*/ or /may't*/ or (Commonwealth) /mee't*/ A
   prefix meaning one level of description higher.  If X is some
   concept then meta-X is data about, or processes operating on,
   X.

   For example, a metasyntax is syntax for specifying syntax,
   metalanguage is a language used to discuss language,
   metadata is data about data, and meta-reasoning is
   reasoning about reasoning.

   This is difficult to explain briefly, but much hacker humour
   turns on deliberate confusion between meta-levels.

   [Jargon File]

   (1999-04-06)


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

meta
 /me't@/, /may´t@/, /mee´t@/, pref.

    [from analytic philosophy] One level of description up. A metasyntactic
    variable is a variable in notation used to describe syntax, and
    meta-language is language used to describe language. This is difficult to
    explain briefly, but much hacker humor turns on deliberate confusion
    between meta-levels. See hacker humor.