synodic month

noun

A month of approximately 29.53 days, measured from a lunar phase until the return of that same phase. The long-term average duration is 29.530 588 days (29 d 12 h 44 min 2.8 s), or about 29 ½ days.

Similar
lunationlunar monthmoon
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Meanings

nounsynodic month (plural synodic months)

plural synodic months

  1. A month of approximately 29.53 days, measured from a lunar phase until the return of that same phase. The long-term average duration is 29.530 588 days (29 d 12 h 44 min 2.8 s), or about 29 ½ days.

    Synonyms: lunation, lunar month

  2. The variably cyclic period from one new moon until the next.

Synonyms & antonyms

nounA month of approximately 29.53 days, measured from a lunar phase until the return of that same phase. The long-term average duration is 29.530 588 days (29 d 12 h 44 min 2.8 s), or about 29 ½ days.

Similar
lunationlunar month

More synonyms by meaning

nounthe period between successive new moons (29.531 days)

Similar
lunar monthmoonlunation
Broader
month
Also see
lunar monthlunationmoon

Synonym sets from Open English WordNet, CC BY 4.0.

Origin

From synodic + month.

Full word history & related roots →

Translations

Persian ماه اقترانی
  • ماه اقترانی (mâh-e eqterâni)month, measured from a lunar phase until the return of that same phase
Romanian lună sinodică
  • lună sinodicămonth, measured from a lunar phase until the return of that same phase
Russian синодический ме́сяц, синодический ме́сяц
  • синодический ме́сяц (sinodičeskij mésjac)month, measured from a lunar phase until the return of that same phase
  • синодический ме́сяц (sinodičeskij mésjac)the variably cyclic period from one new moon until the next
  • лу́нный ме́сяц (lúnnyj mésjac)the variably cyclic period from one new moon until the next
Cite this entry
APA

synodic month. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/synodic%20month

MLA

“synodic month.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/synodic%20month. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “synodic month,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/synodic%20month.

Source: synodic month on Wiktionary, CC BY-SA 4.0.