Answer Description

The PCI expansion slot in a laptop is referred to as miniPCI. These slots can be used for an array of different add-ons, including WiFi cards.

Wikipedia

Peripheral Component Interconnect (PCI) is a local computer bus for attaching hardware devices in a computer and is part of the PCI Local Bus standard The PCI bus supports the functions found on a processor bus but in a standardized format that is independent of any given processor's native bus Devices connected to the PCI bus appear to a bus master to be connected directly to its own bus and are assigned addresses in the processor's address space It is a parallel bus, synchronous to a single bus clock Attached devices can take either the form of an integrated circuit fitted onto the motherboard (called a planar device in the PCI specification) or an expansion card that fits into a slot