What word describes the highest point in the orbit of a celestial body?

The word that describes the highest point in the orbit of a celestial body is "apogee." In astronomical terms, the apogee refers specifically to the point in an orbit where the orbiting body is farthest from the Earth or the object it is orbiting, such as the moon or a satellite. This concept is essential in understanding celestial mechanics and the behavior of orbits.

The other choices do not pertain to this context. "Anodyne" refers to something that soothes or relieves pain, while "artless" describes someone who is straightforward, natural, or lacking deceit. "Arrant" means complete or utter, often used to describe something that is obviously bad or false. These definitions do not align with the concept of celestial orbits, making "apogee" the fitting term in this scenario.