WiFi is the term referred to for wireless networking with computers. The term Wi-Fi tells you that either equipment will work with a wireless network or that a facility has wireless networking available.
If you are looking for a hotel or restaurant where you can connect your laptop or tablet to a wireless network then usually you will see them say either Wi-Fi available or wireless Internet available.
If you are buying a device you want to use on your wireless network (laptop, router, printer, network card, etc) then you want to watch for a clearer definition of the speed. IEEE has created standards for networking so we can use different manufacturer’s products on the same network. For wireless networking the standard is 802.11 You will see a letter after that number that tells you the speed those devices can communicate at. They can communicate with slower devices in which case they operate at the lower speed. Normally when you get a device you want to get one at the highest speed so as you replace parts your networking speed will increase.
The speeds of wireless networks are shown as letters with B, G and N being the current ones. You may see Z mentioned but it is still in development and involves changing ways the devices communicate to increase speeds. B was the original popular wireless networking. It worked at 11 mbps (megabits per second) and you still see it in use. G became popularly available in about 2006 and operates at 54 mbps so is about 5 times as fast as B. N came available just a few years ago and the top speed on it is above 100 mbps and the standard says can push on up toward 200 mbps, but devices today operate at 100-120mbps. If you were to get a device or PC to use on a wireless network today you would want N which works with G and B and is usually 100-120mbps. You will see some manufactures say they have turbo or super N or another similar term and that it works at a higher speed. However these devices will only work at the turbo speed communicating with another device by the same manufacturer rated the same way, but will operate at normal N (and B and G) with other manufacturers.
Thanks Rodney for the question.