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

Overnight hiking is more specifically called 'backpacking'. The word 'hiking' is understood in all English-speaking countries, but regional terms also exist. In the United Kingdom, the activity is often simply called 'walking'. Australians use the term bushwalking for both on- and off-trail hiking. New Zealanders commonly employ the word tramping, particularly for overnight trips. Hiking in the mountainous regions of Nepal and India is sometimes called 'trekking'. Hiking a long-distance trail from end to end is often referred to as thru-hiking.

Comparison with other forms of touring
Hiking is one of the fundamental outdoor activities on which many others are based. Hiking is the only way to reach many beautiful places overland. Enthusiasts regard hiking as the best way to see nature. It is seen as better than a tour in a vehicle of any kind (or on an animal; see horseback riding) because the hiker's senses are not intruded upon by distractions such as windows, engine noise, airborne dust in large quantities, and fellow passengers. It has an advantage over standing in one place because the hiker may cover a wide area.

On the other hand, hiking over long distances or over difficult terrain does require some degree of physical ability and knowledge, as well as a backpack to carry food, water and essential equipment. Hikers may be caught in inclement weather or suffer mishaps. Some countries (and thankfully not here)  require inadequately prepared hikers to pay for their own rescues.