Stalk (4)
I believe the answer is:
stem
'stalk' is the definition.
(synonyms)
This is all the clue.
(Other definitions for stem that I've seen before include "Thwart; support" , "Slender vertical part, glass or plant" , "Slender upright part of wine glass" , "Ski turn and plant stalk" , "Basic skiing turn" .)