What term is used by surveyors to denote a designated reference point for elevation?

In surveying, the term "datum" refers to a designated reference point that provides a baseline for measuring elevation. It serves as a fixed starting point from which vertical distances can be measured, ensuring consistency and accuracy in surveys. This reference is crucial for determining the height of land, buildings, and other structures relative to sea level or another established reference point.

While "benchmark" is also a common term used in surveying, it is specifically a point with a known elevation that has been marked and is used for precise measurements in the field. "Elevation marker" is less commonly recognized as a standardized term in professional surveying contexts, and "topography" relates to the arrangement of the physical features of an area rather than a specific reference point for elevation measurements. Thus, "datum" is the most accurate term to denote a designated reference point for elevation.