The Collaborative International Dictionary of English v.0.48:

EBCDIC \EBCDIC\ ([e^]b"s[e^]*d[i^]k`), n. [acronym from Extended
   Binary Coded Decimal Interchange Code.] (Computers)
   a 8-bit code for representing alphanumerical information in a
   digital information storage medium. It was used expecially on
   IBM mainframes, and differed substantially from the ASCII
   code. [acronym]
   [PJC]

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

EBCDIC
       Extended Binary-Coded Decimal Interchange Code


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

EBCDIC
 /eb's@?dik/, /eb?see`dik/, /eb?k@?dik/, n.

    [abbreviation, Extended Binary Coded Decimal Interchange Code] An alleged
    character set used on IBM dinosaurs. It exists in at least six mutually
    incompatible versions, all featuring such delights as non-contiguous letter
    sequences and the absence of several ASCII punctuation characters fairly
    important for modern computer languages (exactly which characters are
    absent varies according to which version of EBCDIC you're looking at). IBM
    adapted EBCDIC from punched card code in the early 1960s and promulgated
    it as a customer-control tactic (see connector conspiracy), spurning the
    already established ASCII standard. Today, IBM claims to be an open-systems
    company, but IBM's own description of the EBCDIC variants and how to
    convert between them is still internally classified top-secret,
    burn-before-reading. Hackers blanch at the very name of EBCDIC and consider
    it a manifestation of purest evil. See also fear and loathing.


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

Extended Binary Coded Decimal Interchange Code
EBCDIC

    /eb's*-dik/, /eb'see`dik/, /eb'k*-dik/,
   /ee`bik'dik`/, /*-bik'dik`/ (EBCDIC) A proprietary 8-bit
   character set used on IBM dinosaurs, the AS/400, and
   e-Server.

   EBCDIC is an extension to 8 bits of BCDIC (Binary Coded
   Decimal Interchange Code), an earlier 6-bit character set used
   on IBM computers.  EBCDIC was [first?] used on the successful
   System/360, anounced on 1964-04-07, and survived for many
   years despite the almost universal adoption of ASCII
   elsewhere.  Was this concern for backward compatibility or,
   as many believe, a marketing strategy to lock in IBM
   customers?

   IBM created 57 national EBCDIC character sets and an
   International Reference Version (IRV) based on ISO 646 (and
   hence ASCII compatible).  Documentation on these was not
   easily accessible making international exchange of data even
   between IBM mainframes a tricky task.

   US EBCDIC uses more or less the same characters as ASCII,
   but different code points.  It has non-contiguous letter
   sequences, some ASCII characters do not exist in EBCDIC
   (e.g. square brackets), and EBCDIC has some (cent sign,
   not sign) not in ASCII.  As a consequence, the translation
   between ASCII and EBCDIC was never officially completely
   defined.  Users defined one translation which resulted in a
   so-called de-facto EBCDIC containing all the characters of
   ASCII, that all ASCII-related programs use.

   Some printers, telex machines, and even electronic cash
   registers can speak EBCDIC, but only so they can converse with
   IBM mainframes.

   For an in-depth discussion of character code sets, and full
   translation tables, see Guidelines on 8-bit character codes
   (ftp://ftp.ulg.ac.be/pub/docs/iso8859/iso8859.networking).

   A history of character codes
   (http://tronweb.super-nova.co.jp/characcodehist.html).

   (2002-03-03)