Ketchup has a fairly recent etymology but has still come a long way in that short time.
The word comes from a 17th century Chinese term ‘kê-chiap’ meaning ‘Brine’ and referred to a sauce made from pickled fish and spices. 18th century British explorers visiting the region brought the term (and the sauce) to England where it was embraced (with a little mispronunciation).
When the sauce reached Britain, the people added a local twist – mushrooms, the sauce quickly became more mushrooms than fish. Tomato ketchup was eventually created as an alternative to traditional ketchup and soon caught on.