pluvial (adj.)

1650s, "pertaining to rain," from French pluvial (12c.), from Latin pluvialis "of or pertaining to rain, rainy, rain-bringing," from (aqua) pluvia "rain (water)," from fem. of pluvius "rainy," from plovere "to rain," from PIE root *pleu- "to flow." Middle English pluvious "rainy" is attested from mid-15c., from Latin pluviosus. In geology, "depending on or arising from the action of rain," by 1859.