The word 'synodic' traces its lineage to the Greek synodos, meaning "a meeting or assembly," which itself is a compound of syn- ("together") and hodos ("way, path, journey"). The literal image is of people or things coming together on the same path. This concept was adopted into Late Latin as synodicus and into astronomy, where it came to specifically describe the period when two celestial bodies (like the sun and moon) appear to meet or come together in the sky from Earth's perspective. The ecclesiastical meaning, relating to a council meeting, preserves the original Greek sense of a convened assembly, while the astronomical term applies the logic of conjunction to the perceived paths of heavenly bodies.

Structure: syn (together) + od (way, path) + ic (adjective suffix) - syn: From Greek, meaning "together, with". It functions as a combining form in English. - od: From Greek hodos, meaning "way, path, journey". It appears in its base form within the English spelling. - ic: A suffix of Greek and Latin origin, used to form adjectives meaning "of, pertaining to, or characteristic of".