Wiktionary
n. (context astronomy English) The dynamics of celestial body subject to mutual gravitational attraction.
WordNet
n. the branch of astronomy concerned with the application of Newton's laws of motion to the motions of heavenly bodies
Wikipedia
Celestial mechanics is the branch of astronomy that deals with the motions of celestial objects. Historically, celestial mechanics applies principles of physics ( classical mechanics) to astronomical objects, such as stars and planets, to produce ephemeris data. As an astronomical field of study, celestial mechanics includes the sub-fields of Orbital mechanics (astrodynamics), which deals with the orbit of an artificial satellite, and Lunar theory, which deals with the orbit of the Moon.
Usage examples of "celestial mechanics".
The fundamental point of this story is the profound interaction between a civilization and the local celestial mechanics of a star system.
Almost any modern worker in celestial mechanics today at one time or another will make a discovery which he later finds is a special case of a problem treated by a long dead genius.