synodic

/sɪˈnɑdɪk/
adjective
  1. Relating to the time it takes for a planet or moon to return to the same position relative to the sun, as seen from Earth.
    • The synodic period of the Moon is about 29.5 days.
    • Astronomers study synodic cycles to predict planetary alignments.
    • The synodic month is longer than the sidereal month because of Earth's orbit.
Antonyms
What does "synodic" mean? | whatsthatwordmean | whatsthatwordmean