lunation vs synodic month

lunation and synodic month both are nouns.

Word	Noun	Adjective	Verb	Adverb
lunation	Yes	No	No	No
synodic month	Yes	No	No	No

As nouns, lunation and synodic month are synonyms defined as:

lunation and synodic month: the period between successive new moons (29.531 days)

Other synonyms of lunation include lunar month, moon.

lunation (noun)	synodic month (noun)
the period between successive new moons (29.531 days)	the period between successive new moons (29.531 days)