Mountain defination

 A mountain is a large landform that stretches above the surrounding land in a limited area usually in the form of a peak. A mountain is generally steeper than a hill. The adjective montane is used to describe mountainous areas and things associated with them. The study of mountains is Orology. The 50 tallest mountains in the world are in Asia. Exogeology deals with planetary mountains, which in that branch of science are usually called montes (singular - mons). The highest known mountain in the Solar System is Olympus Mons on the planet Mars (elevation 21,171 m).

About...

 There is no universally-accepted definition of mountain. Elevation, volume, relief, steepness, spacing and continuity has been used as criteria for defining a mountain. In the Oxford English Dictionary a mountain is defined as "a natural elevation of the earth surface rising more or less abruptly from the surrounding level and attaining an altitude which, relatively to the adjacent elevation, is impressive or notable." In the United States, the following points of measurement have been used and taught in geography classes: • Flat to 500 feet, base to highest point - Rolling Plain • Highest point 501 to 999 feet above base - Hill • Highest point 1000 feet or more above base - Mountain 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, which makes it ten feet short of the minimum for a mountain in American appellation. Other definitions of "mountain" include: • Height over base of at least 2,500m • Height over base of 1500-2500m with a slope greater than 2 degrees • Height over base of 1000-1500m with a slope greater than 5 degrees • Local (radius 7 km) elevation greater than 300m, or 300-1000m if local (radius 7 km) elevation is greater than 300m By this definition, mountains cover 64% of Asia, 25% of Europe, 22% of South America, 17% of Australia, and 3% of Africa. As a whole, 24% of the Earth's land mass is mountainous and 10% of people live in mountainous regions. Most of the world's rivers are fed from mountain sources, and more than half of humanity depends on mountains for water.

Types...

 Mountains can be characterized in several ways. Some mountains are volcanoes and can be characterized by the type of lava. Other mountains are shaped by glacial processes and can be characterized by their glaciated features. Still others are typified by the faulting and folding of the Earth's crust, or by the collision of continental plates via plate tectonics (the Himalayas, for instance). Shape and placement within the overall landscape also define mountains and mountainous structures (such as butte and monadnock). Finally, mountains can be characterized by the type of rock that make up their composition.