What is the name of the three-dimensional coordinate system with a defined origin and orthogonal axes used for referencing geographic locations?

The International Terrestrial Reference System (ITRS) is the appropriate term for the three-dimensional coordinate system that features a defined origin and orthogonal axes for referencing geographic locations. The ITRS provides a global framework for accurately locating points on the Earth's surface in three dimensions—latitude, longitude, and elevation—allowing for consistent and precise geospatial referencing.

This system is essential for applications such as satellite positioning, surveying, and mapping, where accuracy in three-dimensional measurements is crucial. It takes into account the Earth's shape, gravitational field variations, and other geophysical parameters, making it a comprehensive standard for scientists and professionals dealing with geospatial data.

In contrast, the other choices refer to various aspects of geospatial referencing but do not describe a complete three-dimensional coordinate system. The World Geodetic System, for example, focuses on the global reference system for geospatial data, largely used for mapping and navigation but is more specific to the two-dimensional plane. A horizontal datum refers to a reference surface for measuring horizontal positions but does not encompass vertical measurements. A vertical datum is concerned with height measurement, providing a reference point for elevation but does not involve the full three-dimensional aspect captured by the ITRS.