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Glite Dictionary
sidereal month

sidereal month

9.8
It takes about 27 days for the Moon to return to the same place among the stars
  • noun
  • /saɪˈdɪəriəl mʌnθ/
  • Specialized
translation icon : mes sidéreo
  • Astronomers measure a sidereal month as the duration needed for the Moon to complete one orbit around the Earth relative to the stars.

That's where you want the this sidereal month output.

Examples

  • A sidereal month lasts about 27.3 days, which is the time it takes the Moon to align with the same stars.

  • Understanding a sidereal month helps in tracking the Moon's position against the background of fixed stars.

  • That's where you want the this sidereal month output.

    Stanford

Surface Forms

sidereal month singular
sidereal months plural

Morphology

sidereal + month

The compound is directly compositional: 'sidereal' means 'relating to the stars' and 'month' is a time span, so 'sidereal month' transparently denotes a month measured relative to the stars. This follows ordinary adjective+noun semantics and is cross-linguistically clear, so a learner who knows both constituents can infer the general meaning (even if they may not know the precise 27.322-day value).

Etymology

Sidereal month uses sidereal from a word meaning 'star' and month for a period of time. It means the time the Moon takes to come back to the same place among the stars, so the word 'star' explains why we measure the Moon by its position against the stars.