1. a borough of central London which contains many important government buildings, including the Houses of Parliament , the offices in Whitehall and Downing Street , and the royal palaces, Buckingham Palace and St James’s Palace . Other well-known places there include Westminster Abbey , St James’s Park , The Mall (1) and Victoria station. The River Thames flows on one side of it.
2. the British Houses of Parliament and British politics in general:
There was a heated debate at Westminster today.