Height is the measure of vertical distance, either vertical extent (how "tall" something or someone is) or vertical position (how "high" a point is). For example, "The height of that building is 50 m" or "The height of an airplane in-flight is about 10,000 m". When the term is used to describe the vertical position from sea level, height is more often called altitude. Furthermore, if the point is attached to the Earth (e.g., a mountain peak), the altitude (height above sea level) is called elevation.