This month features two full moons, with the second known as a blue moon, which occurs due to the lunar calendar not aligning perfectly with the Gregorian calendar, resulting in an extra full moon every 2-3 years. The term "blue moon" has a relatively recent definition that emerged from an astronomer's attempt to clarify a more complex explanation found in the Farmer's Almanac related to Lent and Easter. The origins of the term date back further, but its current usage has evolved over time. Additional resources, including a Wikipedia page and a CNN article, provide further insights into the phenomenon. Understanding the blue moon highlights the fascinating interplay between lunar cycles and our calendar system.