My Chinese hasn't got to the level where I'd come across words like '流量' yet, but I'm guessing you might be referring to 3G/4G: http://www.3g.co.uk/PR/Feb2012/3g-what-is-3g-explained-in-simple-terms.html

Is that what it's called when you use a device as a router so other devices can connect? That's called a 'hot spot' (if you want to be specific, say 'wifi hot spot').

给你中国移动香港的网站参考一下。 http://www.hk.chinamobile.com/en/services_plan/4G3G/data.html 里面有答案

你可以造句用流量吗？我搜索的时候每一个释义都有关交通，血，水等等。