Dictionary.net

(BCD, packed decimal) A number representation where anumber is expressed as a sequence of decimal digits and theneach decimal digit is encoded as a four-bit binary number (anibble). E.g. decimal 92 would be encoded as the eight-bitsequence 1001 0010.In some cases, the right-most nibble contains the sign(positive or negative).It is easier to convert decimal numbers to and from BCD thanbinary and, though BCD is often converted to binary forarithmetic processing, it is possible to build hardware thatoperates directly on BCD.[Do calculators use BCD?]