What is a Dongle

Here's a good one for you. I need a 'dongle' apparently for visiting a resort where they don't have wireless internet, but they have broadband. We have emailed back and forth and seem to be talking at cross purposes. The guys in Staples thought I was being rude when I asked them!!! Anyone out there got an answer? My netbook has wifi - so it's not a wifi dongle. Or is it?