Where is 'main street'? has 'main street' a special meaning?

English. Street names denote the streets purpose or use. Some tell that it is on the route to some other city. High street, Church street, Mill street, whatever...London Road. Eastern USA cities did the same. Look at a map. 'Main Street' is a writer's invention. It means different things...think 'ordinary' or 'middle'...maybe 'common'.