There are several synonyms for the term "height above sea level" that are commonly used in geography and navigation. One such synonym is "elevation," which refers to the vertical distance between a point on the earth's surface and the reference datum, which is defined as mean sea level. Another synonym is "altitude," which is often used interchangeably with elevation in aviation and space exploration. Additionally, the term "height above datum" can also refer to the same concept, and is often used in cartography and surveying. Regardless of the specific term used, knowing the height above sea level is crucial for accurate mapping, navigation, and understanding of the earth's terrain.