Parameter Tree:
EARTH SCIENCE > TERRESTRIAL HYDROSPHERE > SURFACE WATER > SURFACE WATER FEATURES > RIVERS/STREAMS

Definition:
River: A large, natural freshwater surface stream having a permanent seasonal flow and moving toward a sea, lake, or another river in a definite channel. Stream: A body of running water moving under the influence of gravity to lower levels in a narrow, clearly defined natural channel.

Reference:
Dictionary of Earth Science, 5th ed. 1997. Sybil Parker, ed. in chief. McGraw-Hill.