Short answers, pulled from the story.
High Street is the primary business and shopping street of a town or city, particularly in the United Kingdom. The word "high" comes from Middle English, where it denoted superior rank, and came to describe the most important street in a settlement from the 17th century onward.
A 2009 statistical compilation counted 5,410 High Streets in the United Kingdom, making it the most common street name in the country. More than 600 of those High Streets are located in London's boroughs.
The 19th century was described as a "golden era" for High Street shops, driven by the rise of the middle class in Victorian England and unprecedented urbanisation fuelled by the Industrial Revolution. Consumer expenditure had grown rapidly from the late 17th and 18th centuries, expanding the number of High Streets across England.
The decline of the British High Street began in the second half of the 20th century, driven first by out-of-town shopping centres and then, from the early 21st century, by online retailers. By 2011, the Portas Review reported that retail spending in High Street shops had fallen below 50 per cent of all retail spending.
Mary Portas is a business consultant best known for the television series Mary Queen of Shops. In 2011, the UK government commissioned her to conduct an independent review of High Street shopping. Her report documented the decline of High Street precincts and made recommendations that have not succeeded in halting store closures.
In the United States, the equivalent is Main Street, while Germany uses Hauptstrasse and Norway uses Storgaten. In Belgium and the Netherlands, the equivalent is Hoogstraat. Ireland predominantly uses Main Street, although some towns including Killarney, Galway, and Kilkenny do have a street specifically named High Street.