A hiker is someone who goes on long walks, usually through natural areas like forests, mountains, or trails. Unlike a casual stroll around the neighborhood, hiking typically means walking for miles on uneven terrain, often up hills or mountains, carrying supplies in a backpack.

Hikers might walk for a few hours on a local trail or spend days backpacking through wilderness areas. They navigate using maps and trail markers, watching for wildlife and enjoying views you can't see from a road. Some famous hiking trails, like the Appalachian Trail, stretch for thousands of miles and take months to complete.

When someone says they're going hiking, they usually mean something more adventurous than a walk in the park: they're heading into nature with proper shoes, water, snacks, and maybe a first-aid kit. A hike (the noun) is the walk itself, so you might say, “We took a five-mile hike up the mountain.”