Rule's was a location in 1890s London.

In 2365, Geordi La Forge (as John H. Watson) wondered he, Data (as Sherlock Holmes), and Katherine Pulaski should head to first as they explored London in Sherlock Holmes Program 3A. He listed three possibilities – the theater, Rule's, or a concert. (TNG: "Elementary, Dear Data")

The oldest restaurant in real-world London is named Rules. It was founded in 1798.