Swimming in the pluvial waters, or inert and caked over by the torrid mud, he would have discovered what he would certainly have regarded as lowly, specially-modified, and degenerate relations of the active denizens of the ocean—the Dipnoi, or mud-fish.
-- H.G. Wells, “Zoological Retrogression”, 1891
Nothing enters her tomb save a little moisture, pluvial in origin, and, it may be, certain mysterious effluvia of which we do not yet know the nature.
-- Maurice Maeterlinck (1862-1949), translated by Bernard Miall, The Life of the Ant, 2001
Pluvial is from the Latin pluvia meaning "rain, water." It shares the Proto-Indo-European root pleu meaning "to flow, to swim" with Pluto, the name of God of the underworld in classical mythology.