I love to go hiking, I wonder if it is popular in other countries.
I'm a big hiker as well. Last year i actually completed the Continental Divide Trail 3100 miles.  The term hiking is really only used in America and Canada. 
And what would be term in others countries ?
Hiking
Hiking is the preferred term, in Canada and the United States, for a long, vigorous walk, usually on trails (footpaths), in the countryside, while the word walking is used for shorter, particularly urban walks. On the other hand, in the United Kingdom, and the Republic of Ireland, the word "walking" is acceptable to describe "all forms" of walking, whether it is a walk in the park or backpacking in the Alps. The word hiking is also often used in
and considered 70% complete. Portions designated as uncompleted must be traveled by roadwalking on dirt or paved roads. This trail can be continued north into Canada to Kakwa Lake north of Jasper National Park by the Great Divide Trail.
The Continental Divide Trail, along with the Appalachian Trail and the Pacific Crest Trail, form what thru-hiker enthusiasts have termed the Triple Crown of long-distance hiking in the United States.
Thru-Hiking.
Only about two hundred people a year attempt to hike the entire trail