stream, river, river or three-stroke river radical (no. 47)
川 centers on flowing water in a channel: a river or stream. The radical sense is the same visible river shape used as a component in other characters.
川 is a pictograph of water flowing in parallel streams or channels. The modern three-stroke form keeps that river-like image clearly.
See the three vertical lines as streams of water flowing side by side through a riverbed: 川 is a river.
For セン, picture 千 (せん, one thousand) tiny streams merging into one 川: 千 -> セン, and all those streams become the river.
river; stream
Kanagawa (prefecture)
Ishikawa (prefecture)
Kawasaki (city)
Kagawa (prefecture)
stream; brook; creek
upper reaches of a river; upstream
big river
rivers
canal
old river
mountain stream
senryū; comic haiku; humorous seventeen-mora poem
mountains and rivers
flood plain; river terrace; riverside area; area between river and river bank
otter (Lutra lutra)
riverside; riverbank
rapids
Sagawa Express (parcel delivery company)
Akutagawa Prize (literary award)