For questions regarding a device that can be programmed to carry out a set of certain set of tasks without external intervention.
A computer is an automated device that is pre-programmed to carry out a certain series of tasks, such as mathematical operations. This includes all of Earth's integrated circuits, as well as theoretical ways to create a similar type of device. Computers are generally used for communication, problem solving including math and general queries.
Consider using that artificial-intelligence tag for questions related to extremely advanced computers that exhibit sentience.