Staunch (flow) (4)
I believe the answer is:
stem
I believe this is a double definition.
'staunch' is the first definition.
(synonyms)
'flow' is the second definition.
(thesaurus)
(Other definitions for stem that I've seen before include "Thin vertical part of glass or plant" , "Restrain the flow of" , "Stalk; stop (flow)" , "Flower's stick" , "Slender upright part, of flower or wineglass" .)