The Collaborative International Dictionary of English v.0.48:
Pluviose \Plu`vi`[^o]se"\, n. [F. See Pluvious.] The fifth month of the French republican calendar adopted in 1793. It began January 20, and ended February 18. See Vend['e]miaire. [1913 Webster]WordNet (r) 3.0 (2006):
Pluviose n 1: fifth month of the Revolutionary calendar (January and February); the rainy month