Altitude

An altitude is a great height. However, any extent or distance of a place upward is mostly measured in relation to sea or ground level, which is also referred to as altitude of the place. It is also measured for an object, such as an aeroplane. In astronomy, for celestial objects, it refers to apparent height measured as an angle above the horizon. However, in geometry, it is the length of the perpendicular line from vertex of the figure to the side opposite of the vertex.