What does synodic mean?
Synodic is an adjective with two specialized uses. In astronomy, it describes a synodic period or cycle: the time between successive conjunctions of a celestial body with the Sun as seen from Earth. For example, the synodic period of Mars is the interval between one opposition of Mars and the next, and it differs from the time Mars takes to complete one orbit because both planets are moving. A synodic month similarly tracks the cycle from one new moon to the next. In an ecclesiastical context, synodic means relating to a synod, an assembly or council of church leaders. The word is uncommon outside these specialized fields and should not be confused with synodic as a synonym for ordinary chronological measurement: a synodic period is specifically based on observed conjunctions. Its unusual combination of ecclesiastical authority and astronomical precision gives it a distinctly specialized character.
adjectiveRelating to a synod, an ecclesiastical council or assembly. In astronomy, it relates to the interval between successive conjunctions of a celestial body with the Sun, as observed from Earth.
- Relating to the interval between successive conjunctions of a celestial body with the Sun, as observed from Earth.
- Relating to a synod or ecclesiastical council.
"The synodic period between successive oppositions of Mars is longer than one of Mars's orbits."
"The synodic month marks the cycle of successive new moons."
"The church's governing body is a synodic council."
A synodic period measures time from what Earth observes rather than from the distant background of fixed stars.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does synodic come from?
Synodic comes through Latin from Greek synodikos, meaning “of or relating to a synod.” The Greek noun synodos was formed from syn-, meaning “together,” and hodos, meaning “way” or “path,” originally suggesting people coming together. The ecclesiastical meaning developed from this sense of assembly, while the astronomical sense arose from the Greek astronomical use of synodos for a conjunction or meeting of celestial bodies.
Related word forms
How synodic is actually used
The word is uncommon in general use. Its astronomical sense is technical, while its ecclesiastical sense is formal and chiefly associated with organized religion.