neptunian

Etymology

From Latin Neptūnius (“of or pertaining to the Roman god Neptune”), from Neptūnus (“the Roman god Neptune”) (possibly ultimately from Proto-Indo-European *nebʰ- (“to become damp, cloudy”)) + -ius (suffix forming adjectives from nouns); analysable as Neptune + -ian. The English word is cognate with French neptunien (“pertaining to the Roman god Neptune, pertaining to the sea, pertaining to Neptunism, Neptunian; proponent of Neptunism, Neptunist”), German Neptunier (“proponent of Neptunism, Neptunist”).