Overlanding is a word that might be new to some, but it's been around for years. The origins of it are up for debate, but in consideration, it's as old as history.
Overlanding in a nutshell is self-supported exploration. So you could say explorers from Europe, travelling on horseback into Mongolia, were the original Overlanders way back in the early centuries.
Nowadays, overlanding is typically vehicle based (4WD's, Motorcycles) touring, where taking a little longer and exploring along the way is the the defining reason for travel.
Overlanding has elements of Camping, Travel, Gear, Culture, Mapping and Geography.
Why not just call it camping? Well, while camping might be one element of overlanding, but you can also just going camping without having to overland.
Say you were to drive 12 hours in a day to arrive at a caravan park and put up a tent and stay for a week, and there is nothing wrong with that, but that is camping. With overlanding, you would probably take the 5 days to drive to your location, stay a night, and then drive home...and that's the difference.
With overlanding, it is widely agreed that the journey is the adventure.
Whatever category you put yourself into, the most important thing is to have fun and look after each other and the environment!