Are you unsure if it's a date or not? Don't worry, there are a few ways to tell. When you arrive, take a look around and see if they've put in effort to create a special atmosphere. If so, it's likely a date. The main way to tell if it's a date is to determine the intentions behind why you meet.
If someone just wants to hang out, then they're not interested in you romantically. However, if there is flirting present, then it's a date. If you're still not sure, wait for it to happen and see what happens. You'll be able to tell fairly quickly if it's a date or not.