ketchup

As nouns the difference between tomato and ketchup

is that tomato is a widely cultivated plant, (taxlink), having edible fruit while ketchup is (uncountable) a tomato-vinegar based sauce.

As a verb tomato

is to pelt with tomatoes.

Catchup is an alternative form of ketchup.

As nouns the difference between catchup and ketchup

is that catchup is a variant of catsup or ketchup while ketchup is (uncountable) a tomato-vinegar based sauce.

Ketchup is a see also of sauce.

As nouns the difference between ketchup and sauce

is that ketchup is (uncountable) a tomato-vinegar based sauce while sauce is a liquid (often thickened) condiment or accompaniment to food.

As a verb sauce is

to add sauce to something.

Ketchup is a see also of sauce.

As nouns the difference between ketchup and sauce

is that ketchup is (uncountable) a tomato-vinegar based sauce while sauce is a liquid (often thickened) condiment or accompaniment to food.

As a verb sauce is

to add sauce to something.

Catsup is an alternative form of ketchup.

As nouns the difference between ketchup and catsup

is that ketchup is (uncountable) a tomato-vinegar based sauce while catsup is (ketchup).