Is it a device? Is it a capability? Is wi-fi mobile, or do we need something like nationwide cellular for true mobile? A lot of companies are marketing the term "mobile," but none seem to really explain what it is.
If this topic isn't appropriate for the topic, please let me know what is and I will move it.
If you use it as a noun, mobile is a cell-phone like device ( "I'm going to call you on my mobile"), as a verb, it describes anything that's portable (mobile printer, mobile computer, mobile phone). WiFi does allow for mobility, so that would be a mobile technology although not in the same sense as a cellular based network. Much like the term high-speed, it can mean anything you say it means.