n.1 the height of an object in relation to a given point, esp. sea level or the horizon.
2 Geom. the length of the perpendicular from a vertex to the opposite side of a figure.
3 a high or exalted position (a social altitude).
Phrases and idioms:
altitude sickness a sickness experienced at high altitudes.
Derivatives:
altitudinal adj.
Etymology: ME f. L altitudo f. altus high