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

Basic Multilingual Plane
BMP

    (BMP) The first plane defined in
   Unicode/ISO 10646, designed to include all scripts in
   active modern use.  The BMP currently includes the Latin,
   Greek, Cyrillic, Devangari, hiragana, katakana, and Cherokee
   scripts, among others, and a large body of mathematical,
   APL-related, and other miscellaneous characters.  Most of
   the Han ideographs in current use are present in the BMP,
   but due to the large number of ideographs, many were placed in
   the Supplementary Ideographic Plane.

   Unicode home (http://unicode.org).

   (2002-03-19)