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a second full moon in a month, occurring every two to three years as a result of the discrepancy between a lunar year and a solar year.

(formerly) the third full moon in a season with four full moons instead of the usual three.

a long, indeterminate stretch of time, as between occurrences of a rare event or phenomenon.

an uncommon phenomenon in which the moon appears to have a blue tinge because of the filtering effect of smoke or dust particles in the atmosphere.

a very long period of time: