An embedded system is a computer that has been built to solve only a few very specific problems and is not easily changed. In contrast, a general-purpose computer can do many different jobs, and can be changed at any time with new programs for new jobs.
An embedded system usually does not look like a computer, often there is no keyboard or monitor or mouse. But like any computer it has a processor andsoftware, input and output. The word embedded means it is built into the system. It is a permanent part in a bigger system.