What is the vertical distance from the surface of the earth to sea level called?

The vertical distance from the surface of the Earth to sea level is referred to as elevation. This term specifically conveys how high a particular point is located above sea level, which serves as a standard reference point for measuring geographic locations. Elevation is commonly used in geography and earth sciences to describe the position of landforms, mountains, or any terrestrial feature in relation to the average height of the oceans, providing context for a variety of processes such as climate, ecosystems, and human activities.

The other terms provided do not accurately describe the concept in question. Depth typically relates to measurements below a reference level rather than above it, making it unsuitable for defining distance above sea level. Height is often used more colloquially but can imply a dimensional measurement that isn't specific to sea level reference. Grade, while related to slope or incline, does not apply to the vertical measurement from the Earth's surface to sea level. Therefore, elevation is the most precise term in this context.