Trekking is to make a slow or arduous journey on foot, especially to hike through mountaineous areas. It is the combination of hiking and walking activitydone in multi-days trip to rural and mountaineous areas with the enjoyment of adventurous and real life scenario.
Etymologically, the word is originated from Dutch word trekken meaning to travel; related to Old Frisian trekka.
Backpacking, the term used for trekking by Wikipedia has been defined as an outdoor recreation where gear is carried in a backpack. Backpacking trips consists of at least one night and can last for weeks or months, sometimes aided by planned resupply points or drops. In present days a good backpacker takes in consideration the impact on environment, including staying on established trails, not disturbing vegetatiion, and carrying garbage out.