The word "computer" has been around since the 1600s. It originally meant someone who performs calculations or computes answers. The original machines we now call computers or more specifically, digital electronic computers, have a rather long history that goes back from today's digital microelectronic circuitry to vacuum tubes to electromechanical to purely mechanical devices.
Charles Babbage is usually credited with inventing the computer in 1832 at Cambridge University in Cambridge England (although the exact year is in question). His original design was for a mechanical difference engine and was designed to be used for calculating solutions for polynomials but he later changed his design to be used for any type of calculation. He never completed the assembly of his design mainly because manufacturing tolerances of that era could not maintain the accuracy he required. His design did not resemble today's computers in any way since it did not use electronics but instead used gears and levers. His work however, was the basis for designs of future computing machines that lead to the computers of today.