Where does the word "ketchup" come from?

The original ketchup had no tomatoes in it. It was made from fish.

Most etymologists trace the word to Hokkien, the Chinese language of southern Fujian and Taiwan. There, kê-tsiap named a brine of fermented fish or shellfish. In a 2012 Slate essay, the Stanford linguist Dan Jurafsky argues that Chinese sailors picked up the sauce from fishing communities in Southeast Asia. Fujianese traders then carried it, and its name, to ports across Southeast Asia.

British and Dutch merchants arrived in the region around 1600 for spices and cloth, and they took to the sauce. The English trader Charles Lockyer toured those ports from 1703. His 1711 handbook, An Account of the Trade in India, said the best ketchup came from Tonkin, in northern Vietnam.

English first recorded the word in 1682. Spelling never settled: catchup appears in 1690 and catsup in 1730, the second in a poem by Jonathan Swift. All three are attempts to write down the same foreign sound.

English cooks soon imitated the imported sauce. Eliza Smith's The Compleat Housewife of 1727 gave a recipe built on anchovies, shallots, vinegar, ginger and nutmeg. Through the 18th century, ketchup became a family of thin, salty sauces. Mushroom and walnut versions were favorites. William Kitchiner's 1817 cookbook offered walnut, mushroom, oyster, cockle, mussel, tomato and cucumber catsups, among others.

The tomato came late. The first known tomato ketchup recipe was published in 1812 in the United States, by the Philadelphia scientist James Mease. Even some tomato recipes of the period kept anchovies, a sign of where the sauce came from. Commercial bottling started in the 1820s, and H. J. Heinz began making ketchup in 1876. According to Jurafsky, the anchovies were gone by the mid-1850s, and American makers such as Heinz sharply raised the sugar around 1890. By 1921, Etymonline notes, "ketchup" on its own meant the tomato kind.

The Hokkien story is the mainstream one, but it is not the only proposal. Etymonline also mentions a possible source in Tulu, a language of south India, where kajipu means curry. It lists Malay kichap, a fish sauce, as another candidate, possibly itself from the Chinese word.

The word has faded in modern Hokkien. Its second syllable survives in many Chinese dialects as a general word for sauce, and Indonesian kecap now means any sauce, usually soy.