Examining the 50 most recent wireless questions, all were about wifi. Braiam previously fixed one that was also tagged Bluetooth (one out of all 317 tagged wireless).
So wireless is overwhelmingly about wifi.
Indeed, that's how people use the term. If someone worries about using too much data on their phone plan because his/her smartphone isn't on wireless at work, that makes perfect sense. Wireless means WiFi. You don't become confused because cell data is wireless. Similarly, if someone suggests turning wireless off on your phone to troubleshoot something, you don't put in in airplane mode.
So just merge it all to wifi, and put a synonym in place. The synonym will help people asking questions, and also anyone trying to search by tag.
If at some point people start using wireless to mean AM radio again, a mod can undo the synonym.