8D or 8-D may refer to: 8D, standard size code for electric batteries 8D Technologies, a Canadian company that develops bicycle-sharing systems. Astair IATA code Eight disciplines problem solving (8Ds) is used to identify, correct, and eliminate the recurrence of quality problems. Eight-dimensional space Expo Aviation IATA code GCR Class 8D, a class of British 4-4-2 steam locomotive Secondary State Highway 8D (Washington), used 1937–1964; became WA 121 in 1964–1967, renumbered WA 141 in 1968 Servant Air IATA code An internet emoticon in which the '8' represents open eyes and the 'D' an open mouth, see List of emoticons Audi A4 B5 (Type 8D) See also D8 (disambiguation)