(1) See printed circuit board and phase change.

(2) (Personal Computer) Any laptop or desktop computer such as a Windows, Macintosh or Linux machine.

(3) (Personal Computer) In contrast to the more generic definition above, PC typically refers to an x86-based desktop or laptop computer, almost all of which run under Windows. PC hardware and operating systems are primarily governed by Intel and Microsoft; however, there are numerous other strong influences. The PC represents the world's largest computer base. More than a billion of them are connected to the Internet, with shipments of new PCs exceeding a quarter million units per year.

PCs are sold by large vendors such as HP and Dell, as well as by thousands of small and large computer dealers who assemble them from standard parts. Ironically, IBM launched the PC in 1981 and exited the business in 2004, selling its PC division to Chinese-based Lenovo.

PC Clients and Servers
The term PC typically refers to the user's desktop or laptop computer, which is called a "client" machine. However, x86-based machines are also widely used for servers, running server versions of Windows such as Windows 2000 and Windows Server 2003, as well as Linux, Unix and other operating systems. See x86-based system.

The IBM PC
IBM launched the PC in 1981, and competitors immediately tried to create PC clones. Except for Compaq, most attempts failed until 1985, when the BIOS chip in the PC was successfully cloned and made available to others. From then on, true compatibles were made by numerous vendors, and the PC industry was established.