#day.time_period  the period of time taken by a particular planet (e.g. Mars) to make a complete rotation on its axis; "how long is a day on Jupiter?"
  supertype:  time_period__period__period_of_time  an amount of time; "a time period of 30 years"; "hastened the period of his recovery"
  subtype:  lunar_day__lunarday  the period of time taken for the moon to make one full rotation on its axis (about 27.3 sidereal days)

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