Soup base (5)
'soup base' is the definition.
(I know that soup base can be written as stock)
This is the entire clue.
(Other definitions for stock that I've seen before include "Neckwear; supply" , "Neck adornment" , "Consomm-like liquid" , "Liquid used as base for soup or sauce" , "Broth" .)
(Other definitions for broth that I've seen before include "Stock" , "Thin soup" , "Type of soup" , "Bouillon" , "Soup made from water in which meat or fish has been boiled" .)