Artificial Intelligence Defined: Useful list of popular definitions from business and science

The world (including marketing) seems to have hit peak-A.I.  Marketers are either marketing to us with A.I. (with a view automating and improving their marketing), or they are actually marketing A.I. to us with products and services infused with A.I. But what exactly is A.I.? In a world of marketing hype and spin, it can be difficult to...