Is it called bandwidth or data?

[Jan]

It doesn't matter what you call it, those people are trained to understand what you're trying to say. If they don't know exactly what you mean, they'll ask a few simple questions to find out.

Bandwidth is usually expressed in Mbps (Megabytes per second), so it means how much data per time frame you can transfer.

Data is nothing more than a collection of bits and bytes. 1's and 0's.
Most people these days want unlimited data, meaning there is no cap on the amount of data that they can transfer each month. Some providers still make use of weekly or monthly data caps, e.g. 40GB/month. When you're dealing with caps, always read the small prints. There is a difference in download data, upload data or combined data. With more and more services like Netflix, people using online radio, youtube etc, most people max out those limits in less than a month. Caps are a thing of the past and providers that still deal with them should lose their customers to companies who allow their clients a bit more freedom.

PS. There is a difference between a home connection and a smart phone. Usually only the phone uses the connection, while at home you have a few computers + a few mobiles. Data transfers on computers are larger than on phones, simply due to the size of the display and the higher qualities that a computer can run at. That being said, when you talk about data or bandwidth, the same principles go for phone, home or even business internet connections.