Stands for "Personal Computer Memory Card International Association." It can also mean, perhaps more appropriately, "People Can't Memorize Computer Industry Acronyms." This way-to-long acronym stands for an association founded in 1989 which develops standards for expansion cards for portable computers.
However, the term is most commonly associated with the actual cards standardized by the organization. These cards are referred to as "PCMCIA cards," or simply "PC cards." There are three types of PCMCIA cards, all of which are rectangular and measure 8.56 by 5.4 cm., but have different widths:
PCMCIA slots also come in three sizes -- a Type I slot can hold one Type I card, a Type II slot can hold one Type II card or two Type I cards, and a Type III slot can hold one Type III card or one Type I and one Type II card. PC Cards can be removed or inserted "on the fly," which means you don't have to turn your computer off to exchange them and you don't have to restart for your computer to recognize them.