Full moon is called a blue moon. The term "blue moon" used in this sense may date to as early as the 16th century, but it became well known in the United States due to the "Farmers' Almanac" (published since 1818). According to the "Farmers' Almanac", a "blue moon" is the third full moon in any period between either solstice and equinox, or between equinox and solstice, (calculated using the mean tropical year), which contains four full moons. These seasons are equal in length, unlike the astronomical ones, which vary in length depending on the Earth's speed in its elliptical orbit round
The Moon is made of green cheese cheese" in this proverb simply refers to a young cheese (sometimes "cream cheese" is used), though modern people may interpret the color reference literally. There was never an actual historical popular belief that the Moon is made of green cheese ("cf.", Flat Earth and the myth of the Flat Earth). It was typically used as an example of extreme credulity, a meaning that was clear and commonly understood as early as 1638. There exists a family of stories in comparative mythology in diverse countries that concern a simpleton who sees a reflection of the Moon and mistakes it for a