Hiking is a form of walking, undertaken with the specific purpose of exploring and enjoying the scenery. It usually takes place on trails in rural or wilderness areas.

The word "hiking" is understood in all English-speaking countries, but there are differences in usage. In some places, off-trail hiking is called "cross-country hiking", "bushwhacking", or "bush-bashing". In the United Kingdom, hiking is a slightly old-fashioned word, with a flavor more of heartiness and exercise than of enjoying the outdoors; the activity described here would be called "hillwalking" or simply "walking". Australians use the term "bushwalking" for both on and off-trail hiking. New Zealanders use "tramping" (particularly for overnight and longer trips), "walking" or "bushwalking". Hiking in the mountainous regions of India and Nepal is sometimes called "trekking". Overnight hiking is called "backpacking" in some parts of the world. Hiking a long-distance trail from end to end is referred to as "thru-hiking" in some places.