I'm an avid hiker-- I got at least once a week if time and weather allows for it. I'm lucky to live in sunny, southern California, so the weather is almost always good for it.
I hear people use the word "trek" a lot in exchange for hiking. Trekking is actually a little bit different than hiking. I'll explain. Hiking is walking for an extended period of time in the wilderness. You need to carry supplies as a just in case, or if you plan on staying overnight somewhere; this then becomes backpacking.
There are hiking trails but they are often made by the people who came before you; people who traversed the woods or hills & made a path. Over time the path looks pretty well man-made.
Trekking, like hiking, is walking for periods of time, but more so on trails that have an exact infrastructure. You don't really need to bring supplies either, other than some water.