A programmable machine. The two principal parts of a computer are:
It responds to a certain set of instructions in a well-defined manner.
It can execute a prerecorded directory of instructions (a program).
Modern computers are electronic and digital. The actual machinery — wires, transistors, and circuits — is referred to as hardware; the instructions and info are identified software.
More About Computer are written Below:
1.  History Of Computer Technology
2.  Kind Of Computers
3.  Computer Components (Hardware)
4.  Usage Of Computer in Our Daily Life