altitude

[In Fr. altitude; Ital. altitudine. From Lat. altitudo = altitude; alt us = high.] A. Ordinary Language: I. Lit. The elevation of an object above its base, or of an object in the air above the surface of the earth. Oft did he take delight To measure th' altitude of some tall crag That is the eagle's birthplace, or some peak, Familiar with forgotten years. Words worth: The Excursion, bk. L II. Figuratively : 1. The highest point in degree of anything. "He did it to please his mother, and to be be partly proud, which he is, even to the altitude of his virtue. -Shakesp. Coriol ., 1. 1. 2. High rank, superiority in wealth or other resources; mental or moral elevation. "Your altitude offends the eyes Of those who want the power to rise." Swift. 3. ( Plural .) Haughty airs. B. Technically: 1. Geom. The altitude of a triangle, parallelogram, or other figure, is the straight line drawn from its vertex perpendicular to its base, or the base produced. (Euclid, bk. vi., def. 4.) 2. Perspective: The altitude of the eye is a right line let fall from the eye perpendicular to the geometrical plane. 3. Trigonom. The same as A., I. An acce ible altitude is one the lower part of which may be approached, so that a base may be measured from it for the purpose of trigonometrical calculation. An inacce ible altitude is one of which the lower part is unapproachable; as, for instance, a castle beyond a river which one has not the means of cro ing. 4. Astron. The elevation of a heavenly body above the horizon, i.e., the arc of a vertical circle intercepted between the centre of the body and the true horizon. It is generally expre ed in,', and". The apparent alt i tude of a heavenly body is the apparent height above the sensible horizon. Its true altitude is its height above the real horizon, after cor rections have been made on account of refraction and parallax. Meridian altitude is the altitude of a heavenly body when pa ing the meridian. The body is then at the highest point it can on that day reach. Observed altitude is the altitude as shown by the instrument with which the observation was taken. Refraction of altitude is the increased elevation given to a heavenly body by refraction. Altitude and Azimuth Instrument. [See AZIMUTH AND ALTITUDE INSTRUMENT.]