Biluna

Biluna is a term used in astronomy and speculative fiction to denote a planetary configuration featuring two notable moons. The word derives from the Latin bi- meaning two and luna meaning moon. In formal science, biluna is not an official designation; it is used descriptively to discuss hypothetical or model configurations in which a planet hosts two large natural satellites that influence each other and the host planet.

In scientific discussions, a bilunar arrangement raises questions about orbital stability, formation scenarios, resonant interactions, and tidal effects. Researchers who model bilunar systems explore how the two moons interact, how their orbits evolve over time, and what observational signatures such a system might produce, such as timing variations or mutual events between the moons. While real-world examples of a clearly dominant two-moon configuration are not standard classifications, the concept helps frame studies of multi-moon dynamics in both our solar system and around exoplanets.

In culture and worldbuilding, biluna often appears as a setting or concept name for a planet with two prominent moons or a world characterized by a binary-moon system. It can be used to evoke unusual stability, beauty, or distinctive celestial dynamics in science fiction, games, and lore.

See also: exomoon, planetary satellite, orbital resonance, tidal interaction, multi-moon system.