PC stands for “personal computer,” which is a computer designed for use by one person at a time. Before PCs existed, computers were enormous machines that filled entire rooms and cost a lot of money. Only big companies, universities, and governments could afford them. The invention of the PC in the 1970s changed everything by making computers small enough and affordable enough for regular people to own.

A PC typically includes a monitor (screen), keyboard, mouse, and a box containing the computer's processing parts. Today, most PCs run the Windows operating system. The term usually refers to desktop computers and laptops, though technically tablets and smartphones can also be considered personal computers.

The abbreviation PC sometimes appears in phrases like “PC gaming” (playing video games on a computer rather than a gaming console) or in comparisons like “Mac or PC?” When people ask that question, they're really asking whether you prefer Apple computers or Windows computers, even though Macs are also personal computers.

In a completely different context, PC can mean “politically correct,” referring to language or behavior chosen to avoid offending particular groups. This meaning has nothing to do with computers, so you need to figure out which PC someone means from context.