Americans have feelings about ketchup. Lots and lots of feelings. Feeling about why ketchup on a hot dog is stupid, and why fancy ketchup is stupid, and why any ketchup at all is stupid. Prepare to have a lot more ketchup-related feelings because you know what? Ketchup, the all-American condiment, is actually Asian.
The word "ketchup" is the Anglicized form of "ke-tsiap," an old Hokkien word for fish sauce. Yes, that fish sauce, the pungent brown liquid used liberally in Southeast Asian cooking. It goes by different names in different countries -- nam pla in Thailand, nuoc nam in Vietnam -- but the Chinese sailors who helped spread it across the region called it ke-tsiap. So when European traders started visiting in the 17th century, that's what they called it too.