Thames, the /temz/ BrE AmE
1 . the longest river in England, which flows from the west into the North Sea. In London, many well-known bridges across the Thames connect the north and south of the city, and many important buildings, including the Houses of Parliament and the Tower of London, are built next to the river:
She lives south of the Thames
2 . set the Thames on fire [usually in negatives] British English old-fashioned to achieve something unusually good or interesting, which makes people notice you:
Phil was making a living as a writer, but nothing to set the Thames on fire.