A microcomputer is a computer that has at its heart a microprocessor central processing unit. In most modern microcomputers the processor also has a short term storage (or cache memory) and input/output control circuits on the same integrated circuit (or chip).
At the turn of the century 30 years later, microcomputers in embedded systems (built into home appliances, vehicles, and all sorts of equipment) most often are 8-bit, 16-bit or 32-bit. Desktop/consumer microcomputers, like PCss, are mostly 32-bit, while some science/engineering workstations as well as database and financial transaction servers are 64-bit (with one or more CPUs).
After the launch by IBM of their IBM PC, the term Personal Computer (q.v.) became generally used for a consumer-friendly microcomputer. The second generation of microcomputers (8-bit, early 1980s) were often referred to as home computers (q.v.).