*synodical*

{ } a. [ L. synodicus, Gr. &unr_;: cf. F. synodique. ] 1. (Eccl.) Of or pertaining to a synod; transacted in, or authorized by, a synod; as, synodical proceedings or forms. “A synodical epistle.” Bp. Stillingfleet. [ 1913 Webster ]

2. (Astron.) Pertaining to conjunction, especially to the period between two successive conjunctions; extending from one conjunction, as of the moon or a planet with the sun, to the next; as, a synodical month (see Lunar month, under Month); the synodical revolution of the moon or a planet. [ 1913 Webster ]