A computer term referring to an inherited set of independent computer systems within an organization (enterprise). The term comes into use as enterprises seek to consolidate the systems of the past into a single information source, either by somehow linking them together so that they can communicate with each other (and with the inquirer) or, more likely, by replacing them with an integrated management information system (IMIS). Hospitals commonly have installed at different times independent computer systems for laboratory, X-ray, business office, and admitting, for example. Unless this legacy system is replaced by an IMIS, (1) it is impossible to obtain a comprehensive view of the hospital’s activities, (2) since much of the same information is found in each system, such as patient demographic data, there is a much higher likelihood of error than if there were a single entry for each piece of information, and (3) there is duplication of cost. Legacy system is also frequently used to describe any previously existing computer system that is considered to be now obsolete and ready for replacement, or incorporation into a new system.