Never one to leave a damsel in distress, I'll have first stab
Back in the past mobile computing meant lugging around a big bag of cables to connect things together. To save all the hassle and weight, several wireless systems were designed:
Bluetooth:
This is a short range system designed to connect bits of electrical/computer gear together. eg PC to laptop, laptop to mobile phone, mobile phone to headset etc etc. In 'theory' you bring the two pieces of equipment together tell each one about the other and they start working together. What they can do depends on each piece of equipment.
WLAN same as WiFi same as 802.11 plus letter:
(Huge simplification): If you talk to someone you communicate by making noises. What the noises mean is a language eg English/French. In computer networking 'ethernet' is the equivalent of the noise and TCP/IP is the language. WiFi is a type of ethernet.
Dotted all over the place are WiFi access points. If your laptop has a WiFi adapter you can connect to these access points and surf the net / send email pretty much as you do at home.
As a diva of the cart sent here, there and everywhere, I suspect the latter is of more use to you.
Hope this helps
EG