A Blue moon is either astronomical event or used in a phrase as a colloquialism.
Astronomical Event[]
A Blue Moon occurs when a month has two full moons in it or four full moons within three months.
Colloquialism[]
Traditionally, the colloquialism Blue Moon means an unusual and not very frequent occurence.
In the World of Nausicaä[]
A Blue Moon seems to be a colloquialism, based upon the sentence structure used [1].
References[]
- ↑ DE1a pg 64
a See Page Conversions Between Editions to convert Deluxe Edition volume 1 (DE1) to other editions