Correct terms for a roadside gutter and gutter on a roof
I don't know this word, so I consult it on the online dictionary and I found 排水沟 for the gutter at the roadsides and 檐沟 or 天沟 for the gutter at the roof.

Actually,it's the first time for me to see 檐沟 or  天沟. After understanding what they mean,I think I would use 排水沟 for both cases.排水沟 means "a ditch to drain out the water".