what is difference between downpour and waterspout
down- + pour
- (UK) IPA(key): /ˈdaʊn.pɔː(ɹ)/
downpour (plural downpours)
- A heavy rain.
- Synonyms: cloudburst, rainstorm
downpour (third-person singular simple present downpours, present participle downpouring, simple past and past participle downpoured)
- (intransitive) To pour down; rain heavily.
- pour down
water + spout
waterspout (plural waterspouts)
- A whirlwind that forms over water, not associated with a mesocyclone of a thunderstorm (contrary to a true tornado).
- A true tornado that passes over a body of water.
- A channel through which water is discharged, especially from the gutters of a roof.
- water tornado
- 1922, Katherine Mansfield, At The Bay 
- Stanley turned over on his back and kicked with his legs till he was a living waterspout.
- dust devil
- fire whirl
(water discharge channel):