The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic system, vertical datum).
In topography, prominence characterizes the height of a mountain or hill summit by the vertical distance between it and the lowest contour line encircling with no higher summit.
Data source: 50 Most Prominent Peaks on Earth (unless otherwise noted)