From TechWeb.com:
PC
(3) (Printed Circuit) See printed circuit board.
(2) (Personal Computer) Any laptop or desktop computer such as a Windows machine or a Macintosh.
(1) (Personal Computer) A stand-alone laptop or desktop computer running Windows (or DOS for earlier applications). PC hardware and operating systems are primarily governed by Intel and Microsoft respectively. The PC is the world's largest computer base.
PCs are also widely used as clients and servers in a local area network (LAN). PC clients predominantly run under Windows, but PC servers (x86-based servers) run under Windows, NetWare or a variation of Unix such as Linux or UnixWare. PC servers may use Windows 95/98, but Windows NT and 2000 are more likely choices.
Although there are literally thousands of PC vendors, from mom and pop shops to large mail order houses (Dell, Gateway, etc.) to the major brands (Compaq, HP, etc.), and of course IBM, still one of the world's largest PC makers, all PCs use an Intel x86 or compatible CPU.
After IBM introduced the PC in 1981, the first attempts at cloning it were mostly unsuccessful. Except for Compaq's first PC, from 1982 to 1985, there were a lot of "almost compatible" PCs. However, as soon as the part of the operating system known as the BIOS was successfully cloned and made commercially available, true compatibles appeared in abundance.
Before Windows 95, adding another peripheral device to a PC was often an exercise in trial and error. Modifying DOS's infamous configuration files (AUTOEXEC.BAT and CONFIG.SYS) caused many a user to give up. Windows 95, 98 and 2000 added Plug and Play, which means for the most part, you can replace hard disks and display adapters, as well as add a scanner, CD-ROM or other device without difficulty.
The PC has become a commodity item, winding its way onto the shelves of retail outlets worldwide. This is a testimonial to the power of a computer standard, even one fraught with loopholes and inconsistencies.
Today, most PCs run most software and work with most plug-in boards. However, with the myriad of adapters and applications available, one device, application or utility can always conflict with another. The way to guarantee that something works is to try it. This has been true since day one in the computer business.
workstation
(1) A high-performance, single-user computer typically used for graphics, CAD, CAE, simulation and scientific applications. A workstation may be a RISC-based computer that runs under some version of Unix or Linux, the major vendors being Sun, HP, IBM and SGI. It may also be a high-end PC using Intel or AMD CPUs from any PC vendor.
(2) A terminal or desktop computer in a network. In this context, workstation is just a generic term for a user's machine (client machine). Contrast with server and host.
(3) In the telecom industry, a combined telephone and computer.
Workstations For years, workstations such as these from Sun, Compaq and SGI (top to bottom) were used for CAD, medical imaging and scientific visualization. Combined with large, high-resolution monitors, they were traditionally Unix-based and pushed the envelope in performance, although Windows NT/2000 PCs have made significant inroads in this market as well. (Images courtesy of Sun Microsystems Computer Company, Compaq Computer and SGI.)