What is Management Information System?

Legal Definition
A management information system (MIS) focuses on the management of information technology to provide efficiency and effectiveness or strategy decision making. The concept may include systems termed transaction processing system, decision support system, expert system, or executive information system. The term is often used in the academic study of businesses and has connections with other areas, such as information systems, information technology, informatics, e-commerce and computer science; as a result, the term is used interchangeably with some of these areas.

Management information systems (plural) as an academic discipline studies people, technology, organizations, and the relationships among them. This definition relates specifically to "MIS" as a course of study in business schools. Many business schools (or colleges of business administration within universities) have an MIS department, alongside departments of accounting, finance, management, marketing, and may award degrees (at undergraduate, master, and doctoral levels) in Management Information Systems.

MIS professionals help organizations to maximize the benefit from investments in personnel, equipment, and business processes.
-- Wikipedia
Legal Definition
The study of information needs as this organized method facilitates at every level in making operational, tactical, and strategic decisions by an organization's management. Designing, implementing, maintaining procedures, processes, and routines to provide suitable, accurate, detailed reports consistently and on time is this group's objective.