A small market has a cashier. When people want to buy things, they form a line and pay one at a time. This line is a queue.
A supermarket may have many cashiers, and each can have its own line. Each of these acts on its own.
If instead we form a single line that is shared by all cashiers, we will have a single line, and each of the cashiers would take the next one, in the same order they were ready.
A queue is a list where things are taken out in the same order they were added.