Origin of ketchup, say (6)
I believe the answer is:
source
'origin' is the definition.
(I know that origin can be written as source)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for source that I've seen before include "Find" , "Origin as of a river" , "From which something springs" , "Origin or starting point" , "Beginning to add" .)