A PC Card is a small, removable device used to add functionality to laptops and other portable computers. Originally known as PCMCIA cards, they can provide features like additional memory, network connectivity, or storage. These cards fit into a dedicated slot on the computer, making it easy to upgrade or change components as needed. There are different types of PC Cards, including Type I, Type II, and Type III, which vary in thickness and purpose. While they were popular in the 1990s and early 2000s, many modern devices now use ExpressCard or USB connections for similar functions, as technology has evolved.