Wireless (or WiFi) is a way that your computer can send and receive information to and from another Wireless-enabled device: e.g. a hub or switch, a router, a printer – without the need to plug in a network cable.
Broadband is a fast connection (in the sense that “it’s faster than what we had before”) between a computer and the internet via a router. You connect your computer to your router (wirelessly or with a cable) and the router connects to the internet (usually via a telephone socket).
Some years ago clients started to request Wireless Broadband, it’s not their fault: communication companies were trying to make money by using a new phrase (see also: The Cloud) that people hadn’t heard before. But Wireless Broadband doesn’t exist (just like The Cloud). You can connect devices to a wireless router. You can have a broadband connection. But, although they can exist within the same piece of kit (a wireless router) they are separate concepts and separate bits of technology.