Catsup is another way to spell and say ketchup, that thick, sweet, tangy red sauce made from tomatoes. Whether the bottle says “catsup” or “ketchup,” you're getting the same condiment for your fries or burger.

For most of the 1800s and early 1900s, Americans used both spellings interchangeably. You might have seen “catsup” on old diner menus or in classic books.

Today, “ketchup” has become the more common spelling, though some brands still use “catsup” on their labels. The pronunciation can differ slightly: catsup is often said like “CAT-sup” while ketchup is often said like “KETCH-up,” but they mean exactly the same thing. If someone asks you to pass the catsup at a cookout, they want the same red tomato sauce you'd call ketchup.