[1] : The Collaborative International Dictionary of English v.0.48

downpour \down"pour`\, n.
   a pouring or streaming downwards; esp., a heavy or continuous
   shower.
   1913 webster

[2] : WordNet (r) 2.0

downpour
     n : a heavy rain syn: cloudburst, deluge, waterspout, torrent,
          pelter, soaker
see also:
cloudburst deluge waterspout torrent pelter soaker 

[3] : Moby Thesaurus II by Grady Ward, 1.0

93 moby thesaurus words for "downpour":
   affluence, afflux, affluxion, brash, burst of rain, cascade,
   cataract, chute, cloudburst, collapse, comedown, concourse,
   confluence, conflux, course, crash, crosscurrent, current, debacle,
   declension, declination, defluxion, deluge, descending, descension,
   descent, down, downbend, downcome, downcurve, downfall, downflow,
   downgrade, downrush, downtrend, downturn, downward trend, drencher,
   drift, driftage, drop, dropping, fall, falling, flood, flow,
   flowing, fluency, flux, gravitation, gush, gushing rain,
   heavy rain, inclination, inflow, inundation, mill run, millrace,
   monsoon, onrush, onward course, outflow, plash, plummeting, pounce,
   pour, race, rainburst, rainspout, rainstorm, rapids, run, rush,
   scud, set, soaker, soaking rain, spate, spout, stoop, stream,
   surge, swoop, thunderstorm, tide, torrent, torrent of rain, trend,
   undercurrent, undertow, water flow, waterfall, waterspout

Downpour >> D Words
Downpour, definition of term: Downpour
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