Wordnet 3.0
VERB (1)
1. 
 precipitate as rain; 
- Example: "If it rains much more, we can expect some flooding"[syn: rain, rain down]
WordNet (r) 3.0 (2006):
rain down
    v 1: precipitate as rain; "If it rains much more, we can expect
         some flooding" [syn: rain, rain down]