ketchup vs tomato ketchup

ketchup and tomato ketchup both are nouns.

Word	Noun	Adjective	Verb	Adverb
ketchup	Yes	No	No	No
tomato ketchup	Yes	No	No	No

As nouns, ketchup and tomato ketchup are synonyms defined as:

Other synonyms of ketchup include catsup, cetchup.

ketchup (noun)	tomato ketchup (noun)
thick spicy sauce made from tomatoes	thick spicy sauce made from tomatoes