Mountain, mount, peak, alp, volcano, mesa denote a relatively steep and high elevation of land.
Mountain, the ordinary and inclusive term, varies somewhat in meaning according to locality. In general it designates an elevation higher and steeper than a hill, rising more or less abruptly from its surrounding country, and standing out conspicuously when viewed from a distance.
Mount is often used in proper names of mountains.
Peak, when applied to a mountain, designates one that rises to a sharp point; it may be isolated or one of a range.
Alp suggests a towering, dizzy, or unscalable height.
Volcano designates a cone-shaped mountain formed chiefly of ejected molten rock or ash and topped, usually, by a crater.
Mesa is used especially in the southwestern part of the United States to designate a flat-topped elevation, usually comparable to a hill in height, but more suggestive of a mountain because of its steep clifflike sides.