NR-010Once in a Blue MoonBook2025

An idiom is a commonly used phrase that cannot be understood from the literal definition of its individual words.

These expressions often appear illogical or puzzling but are widely understood within a language community to carry a specific, figurative meaning. Idioms are part of the informal, often colourful fabric of everyday speech, and many have historical or cultural origins that are no longer obvious today.

Once in a Blue Moon is a book exploring 100 idioms and their origins.

Blue Moon, October 2020 (NASA's Scientific Visualization Studio)