Meaning of binary-coded decimal system

bi'na•ry-cod•ed dec'imal sys"tem

Pronunciation: (bī'nu-rē-kō"did, -ner-ē-), [key]
  1. a numerical system in which each decimal digit is represented by a unique collection of binary digits, not necessarily the same as those used in binary notation. Abbr.: BCD
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.