(1) The region of a mountain above the tree line.
(2) Of or relating to high mountains.
(3) Terrain above timberline in the mountains, which varies in elevation among mountain ranges. In the United States "alpine" applies to areas high in the Rocky Mountains, the Cascades, and the Sierra Nevada. The Appalachian Mountains have alpine areas, but these are in smaller isolated pockets. Regardless of where it exists the alpine zone is a fragile environment. A simple stroll off an established trail crushes delicate plants such as heather, so it is important to stay on existing trails in alpine areas.
(1) This all started in the Alps, which are the definition of alpine.
(2) Like in the Alps. Get it?