What is "walnut ketchup"

ketchup \ketch"up\, n. [Probably of East Indian origin, because it was originally a kind of East Indian pickles. Cf. also Malay k[e^]chap fish sauce.
--MW10.] A pureed table sauce made predominantly from tomatoes, flavored with onions, sugar, salt and spices; called also tomato ketchup. The term is also applied to pureed sauces containing mushrooms, walnuts, etc., being called in such cases mushroom ketchup, walnut ketchup, etc. [Written also catsup and catchup.]

Catchup \Catch"up\, Catsup \Cat"sup\, n. [Probably of East Indian origin, because it was originally a kind of East Indian pickles. Cf. also Malay k[e^]chap fish sauce.
--MW10.] A pureed table sauce made predominantly from tomatoes, flavored with onions, sugar, salt and spices; called also tomato ketchup. The term is also applied to pureed sauces containing mushrooms, walnuts, etc., being called in such cases mushroom ketchup, walnut ketchup, etc. [Written also ketchup.]