What does bus mean in bus bar?

Bus bars are actually simple conductor strips of copper using for connection between one system to another.for example transformer to panel. bus ducts are enclouser of that bus bar

When it's an airbus!When it Turns in to a street!

On the bus because the bus isn't a fixed place

One before the (anything) last

The drivers have remote key to open the bus door even if they dont have any key at all.