Modern invented compound of Luna (Latin 'moon') and Bella (Latin/Italian 'beautiful').
Lunabella is a name of unapologetic romanticism, a compound of two ancient words that together paint a picture of moonlit beauty. "Luna" comes directly from the Latin word for moon and was the name of the Roman goddess of the moon, counterpart to the Greek Selene, who drove her silver chariot across the night sky. Luna governed tides and seasons, dreams and transformation; her name was spoken in Roman homes where the moon's phases marked the calendar.
K. Rowling's Harry Potter series, who made the name synonymous with gentle otherworldliness. "Bella," the second element, is the Italian and Latin word for beautiful, with deep roots in medieval European naming: Isabella was borne by queens of France, England, and Spain, and the diminutive Bella appeared across Italian Renaissance literature as a term of endearment.
The pairing of Luna and Bella creates a name that means, essentially, "beautiful moon" — a phrase that appears in the poetry of cultures from Japanese (tsukimi, moon-viewing) to Arabic (qamar jameel) to Romantic-era English verse. Lunabella belongs to the same family of celestial compound names as Stella Maris and Aurora, names that look upward for their imagery. It suits a world increasingly enchanted by cosmic themes in culture, from astrology's renaissance to space exploration narratives. The name is long and ceremonial, often shortened to Luna or Bella in everyday life, but it carries its full weight beautifully on a birth certificate.