WiFi networks can operate in a number of configurations, from point-to-point, point-to-multipoint, and multipoint-to-multipoint.
Point-to-point is simply a network of two. Multipoint-to-multipoint is where any node of the network can communicate with any other and is often called an ad-hoc, peer-to-peer or mesh network.
The most common configuration is point-to-multipoint, where a central access point is host to numerous client devices. This is also known as Infrastructure mode. An example of which might be a wireless router in your home with several laptops, phones, game consoles and the like connected. For the most part, this is the configuration we will be focusing on with the WiFi Pineapple.