PCMCIA
Personal Computer Memory Card International Association (PCMCIA) is an industry standards group that promotes the former PC Card and current ExpressCard peripheral device interface form factors, which are targeted mainly towards laptop computers.
PC Card
The PCMCIA group's original specification was self named, and consequently products developed for this new form factor were referred to as PCMCIA devices. The PCMCIA body, in development of the second version of the specification, changed the standard's name to PC Card. Despite the name change, PC Card devices are still commonly referred to as PCMCIA devices. This can lead to a bit of confusion, especially when discussing the PCMCIA's later ExpressCard standard, if one is not aware or distinguishes between "PCMCIA, the standards body" and "PCMCIA, the misnomer for a PC Card device".
There were a number of different types of PC Card. In respect to their use for TV card devices, it is the CardBus type of PC Card that is of interest.
ExpressCard
ExpressCard is the latest peripheral device interface form factor developed by the PCMCIA standards body, and it is meant as a replacement for their former PC Card specification.
It should be noted that ExpressCards are not compatible with CardBus, nor vice versa.