The absolute height of a location, usually measured from sea level. / A vertical distance. / (geometry) The distance measured perpendicularly from a figure's vertex to the opposite side of the vertex.

plural of altitude

plural of absolute altitude

plural of critical altitude

the altitude at which atmospheric pressure becomes constant as altitude increases

(idiomatic, archaic) drunk.

(aviation) The vertical distance between the airplane and the surface below.

plural of transition altitude

(aviation) The altitude (which varies by country) above which an aircraft's barometric altimeters are set as if the sea-level atmospheric pressure were equal to 1013.25 hectopascals (regardless of the actual atmospheric conditions) and altitudes are reported as flight levels.

(aviation) A measure of altitude inferred by the measurement of ambient pressure in differential with a reference pressure at a known altitude.