Definition of lunar day in English:

lunar day


  • 1The interval of time between two successive crossings of the earth's meridian by the moon (roughly 24 hours and 50 minutes)

    • ‘Based on lunar day of 24 hrs 50 minutes, will provide accurate indication of tide cycle.’
    • ‘The lunar day is 50 minutes longer than a solar day because the moon revolves around the Earth in the same direction that the Earth rotates around its axis.’
    • ‘The length of the lunar day is thus identical to the length of its revolution around Earth.’
    • ‘The moon's orbit, and hence the tidal bulges, are tilted relative to the earths equator, resulting in the 2 high waters per lunar day not being equal to each other.’
    • ‘Thus their ‘day’ would not be based on the movement of the Sun, a 24-hour cycle, but rather a lunar day, lasting 24 hours and 50 minutes.’
  • 2rare The interval of time between two successive sunrises as seen from the moon.

    • ‘It was designed to operate for three lunar days, but the scientific team succeeded in keeping it operating for eleven lunar days - the equivalent of 10 months.’
    • ‘Over the month-long lunar day, we'd see the Earth turn in place every 24 hours.’


lunar day

/ˈlunər deɪ/