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.
Today's students can put dope in their veins or hope in their brains. If they can conceive it and believe it, they can achieve it. They must know it is not their aptitude but their attitude that will determine their altitude. Jesse Jackson
A review of summit day photographs will show that I was clothed in the latest, highest quality, high altitude gear, comparable, if not better, than that worn by the other members of our expedition. Anatoli Boukreev