In linguistics and grammar, a pronoun is a word that substitutes for a noun or noun phrase. It is a particular case of a pro-form.
IP Routing is an umbrella term for the set of protocols that determine the path that data follows in order to travel across multiple networks from its source to its destination. Data is routed from its source to its destination through a series of routers, and across multiple networks.
An IP Gateway is needed to provide the communications between your computer and the World Wide Web. A Network Switch can send the data, or packets, to the intended computer because of the capabilities of an IP Gateway Router.