Boy's rhyme for 'sauce' (3)
I believe the answer is:
soy
'for sauce' is the definition.
(soy sauce)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for soy that I've seen before include "Oriental sauce" , "Dark salty sauce" , "Sauce bean" , "Piquant eastern sauce" , "Chinese sauce" .)