SOUTH PLATTE RIVER(noun) Did you mean: Synonyms Rhymes Definitions There is 1 meaning of the phrase South Platte River. South Platte River - as a noun A tributary of the platte river Synonyms (Exact Relations)south platteWord Variations & RelationsStarts S Starts SO Starts SOU Starts SOUT Ends R Ends ER Ends VER Ends IVER Starts S & ends R Starts SO & ends R Starts S & ends ER A-Z Proximitiessouterly 11souterrain 10souterrains 11souters 7south 8 South Platte River south-centralsouth-eastsouth-polarsouth-southeastsouth-southwest