tributary_of
x tributary_of y if and only if x a channel for the flow of a substance into y, where y is larger than x. If x and y are hydrographic features, then y is the main stem of a river, or a lake or bay, but not the sea or ocean. If x and y are anatomical, then y is a vein.
RO:0002375
in_branching_relationship_with
is_a