An information system that supports business or organizational decision-making activities.
Sprague  defines a properly termed DSS as follows:
- DSS tends to be aimed at the less well structured, underspecified problem that upper level managers typically face;
- DSS attempts to combine the use of models or analytic techniques with traditional data access and retrieval functions;
- DSS specifically focuses on features which make them easy to use by non-computer-proficient people in an interactive mode; and
- DSS emphasizes flexibility and adaptability to accommodate changes in the environment and the decision making approach of the user.
 Sprague, R;(1980). “A Framework for the Development of Decision Support Systems.” MIS Quarterly. Vol. 4, No. 4, pp.1-25.