synodic
adjective
syn·od·ic sə-ˈnä-dik 
variants or synodical
sə-ˈnä-di-kəl
1
: of or relating to a synod : synodal
2
usually synodic [Greek synodikos, from synodos meeting, conjunction] : relating to conjunction
especially : relating to the period between two successive conjunctions of the same celestial bodies (such as the moon and the sun)
Example Sentences
Recent Examples on the Web These rotations are called the synodic cycles of the planets—their cycles relative to the sun. 
Tony Freeth, Scientific American, 15 Dec. 2021 This writing is a formulaic list of the synodic events of each planet (such as its conjunctions with the sun and its stationary points) and the intervals in days between them. Tony Freeth, Scientific American, 15 Dec. 2021 For example, the interior face of the iconic Reverso cradle features three lunar displays (the synodic cycle, the draconic cycle and the anomalistic cycle). Victoria Gomelsky, Robb Report, 20 Aug. 2021
Tony Freeth, Scientific American, 15 Dec. 2021 This writing is a formulaic list of the synodic events of each planet (such as its conjunctions with the sun and its stationary points) and the intervals in days between them. Tony Freeth, Scientific American, 15 Dec. 2021 For example, the interior face of the iconic Reverso cradle features three lunar displays (the synodic cycle, the draconic cycle and the anomalistic cycle). Victoria Gomelsky, Robb Report, 20 Aug. 2021 Word History
First Known Use
1561, in the meaning defined at sense 1