The last post and the one before it have dealt with words derived from Latin luna, which arose as a compound based on the Indo-European root for ‘light’ that also led to Spanish luz. The Romans used luna not only for the moon itself, but for what they imagined to be the goddess of the moon; in light of that, we write the capitalized Luna as the name of that ancient lunar goddess. To this day some parents choose Luna as a first name for a newborn girl, and Luna is even more common as a Spanish family name.
The French descendant of luna is lune, which English has carried over as a geometrical term for ‘a figure in the form of a crescent, bounded by two intersecting arcs of circles’; the definition has also been scaled up to three dimensions, in which case lune designates ‘the portion of the surface of a sphere bounded by two great circles.’ Spanish conveys the same notion with lúnula, a Latin diminutive that meant literally ‘little moon’ but typically referred to an ornament of that shape that Roman women were accustomed to wearing. In English, a lunula or lunule is ‘the crescent-shaped area at the base of a fingernail,’ for which Spanish again uses lúnula.
© 2011 Steven Schwartzman