A mountain is a large landform that stretches above the surrounding land in a limited area usually in the form of a peak. The adjective montane is used to describe mountainous areas and things associated with them.
The highest mountain on earth is the Mount Everest (elevation 8,848 m).
Whether a landform is called a mountain may depend on usage among the local people. The highest point in San Francisco, California, is called Mount Davidson, notwithstanding its height of 990 feet. Similarly, Mount Scott outside Lawton, Oklahoma is only 824 feet from its base to its highest point.
High mountains, as well as those located close to the Earth's poles, reach into the colder layers of the atmosphere. They are consequently subject to glaciation, and erosion through frost action. Such processes produce the peak shape. Some of these mountains have glacial lakes, created by melting glaciers; for example, there are an estimated 3,000 glacial lakes in Bhutan. Mountains can be eroded and weathered, altering their characteristics over time.
Source: en.wikipedia.org/wiki/Mountains - 25.03.2010
Whether cliffy rocks or green mountain sides: for me the mountain environment is always especially full of character and touching.