Synodic \Syn*od"ic\, Synodical \Syn*od"ic*al\, a. [L. synodicus, Gr. ?: 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]

Source: The Collaborative International Dictionary of English v.0.48
 

Synodic \Syn*od"ic\, Synodical \Syn*od"ic*al\, a. [L. synodicus, Gr. ?: 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.

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.

Source: Webster's Revised Unabridged Dictionary (1913)