Noun
Space extended upward; height; the perpendicular elevation of an object above its foundation, above the ground, or above a given level, or of one object above another; as, the altitude of a mountain, or of a bird above the top of a tree.
The elevation of a point, or star, or other celestial object, above the horizon, measured by the arc of a vertical circle intercepted between such point and the horizon. It is either true or apparent; true when measured from the rational or real horizon, apparent when from the sensible or apparent horizon.
The perpendicular distance from the base of a figure to the summit, or to the side parallel to the base; as, the altitude of a triangle, pyramid, parallelogram, frustum, etc.
Height of degree; highest point or degree.
Elevation of spirits; heroics; haughty airs.
Source: Webster's dictionarythe altitude gave her a headache Source: Internet
;1000 ft rule :An aircraft must maintain an altitude of 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet of the aircraft over any congested area of a city, town, or settlement, or over any open air assembly of persons. Source: Internet
;500 ft rule :An aircraft must maintain an altitude of 500 feet above the surface, except over open water or sparsely populated areas. Source: Internet
Above sea level to an altitude of convert, the islands have a mixture of tropical, subtropical, and temperate climates. Source: Internet
According to Kirk & Raven (reference cited below), all you need for this feat is three straight sticks pinned at one end and knowledge of your altitude. Source: Internet
According to Speer, Hitler felt its superior speed compared to other fighters of the era meant it could not be attacked, and so preferred it for high altitude straight flying. Source: Internet