Mostly yes, Stella. Ketchup refers to the condiment and tomato sauce refers to the type of sauce you would serve on pasta. But you might find (especially in the UK or Ireland) that some people also say "tomato sauce" for both, and you will know which one it is by the context.

What a debatable topic! In America, "ketchup" is for putting on hot chips, and "tomato sauce" is for pasta and pizza, etc. In Australia and the UK, we don't use the word "ketchup" very much, only occasionally, if we're trying to differentiate between the two. There's one company in Australia that makes two varieties of what Americans call "ketchup", one is called "ketchup", which is a little bit sweeter, spicier and darker in colour than the other one, which is called "tomato sauce". If you asked me to go to the supermarket and buy a bottle of "tomato sauce", I would come back with ketchup. If you want the other kind, you'd need to ask me for "tomato PASTA sauce". It's a confusing topic to discuss!

You're right! In the USA, Ketchup -also known as Catsup, would never be confused with Tomato Sauce. Ketchup does have many of the same ingredients, but it's flavor is marked by White Vinegar and Corn Syrup, and I've never seen a bottle of it here marked as "Tomato Sauce". We do light-heartedly debate such trivial things as what to call the tomato concoction often served over pasta, too. Many people (Mostly us Italian-Americans) say it's called simply "Sauce" and argue with the alternate "Gravy". But Gravy to me contains meat, also known as Ragout. There is another playful argument about what foods Ketchup is added to. Some (like me) say that ketchup is for only Fried Potatoes and Hamburgers. God forbid one puts ketchup on a Hot Dog! Hot dogs get Mustard only! Others can not eat fried eggs without ketchup all over them. Yuk! There are many who put ketchup on EVERYTHING. I think they are addicted to the high sugar content of ketchup. Stikytape, I remember visiting Perth, and stopping into a "Hungry Jacks" and being shocked to see beets on the hamburger I ate :)