What is "Wi-Fi", and what is a "Wi-Fi hotspot"?

Wi-Fi stands for "Wireless Fidelity" and it's simply a way for your computer (be it notebook, pc) to connect to a wirelessly shared network, usually for the purpose of high speed internet sharing. A wi-fi hotspot is a place designed for people to come with their laptops, pay a nominal fee (if applicable) and surf the internet where the hotspot is, away from home or an office. Some cities, like here in Sacramento, CA are implementing city-wide wi-fi, essentially turning the whole city into a hotspot. Hotspots are usually through AT&T or T-Mobile, and can be found in bookstores, coffee shops, airports, etc.