Wikipedia
Thru-hiking is hiking a long-distance trail end-to-end. In United States, the term is most commonly associated with the Appalachian Trail (AT), the Pacific Crest Trail (PCT), and the Continental Divide Trail (CDT), but also refers to other end-to-end hikes. Other examples include the Te Araroa Trail in New Zealand, the Camino de Santiago in Spain, the Lycian Way in Turkey, the Israel National Trail, and the Great Divide Trail (GDT) in Canada. Thru-hiking is also called "end-to-end hiking" or "end-to-ending" on some trails, like Vermont's Long Trail or New York's Long Path and Northville-Placid Trail. Section hiking, on the other hand, refers to hiking a trail one section at a time, without continuity and not necessarily in sequence with the other sections.