Hiking is an outdoor activity of walking in beautiful natural environments on pre-charted paths called hiking trails. There are day hikes and overnight hikes.
Trekking is a long journey be undertaken on foot in areas where there are usually no means of transport available. Trekking is not necessarily mountaineering; it is walking for a number of days, usually on uncharted paths, in challenging environments which are likely to be hilly or mountainous.
Namely days 