Queues
A list of data items, commands, etc., stored so as to be retrievable in a definite order.
Workflows are comprised of queues. Documents route through workflow queues until they reach their end destination. Often, in each queue an action is performed (automatically, by a user, or by a script).
Unique ID
A special index key typically used as one of the five customizable document keys. If used, this key will generate a unique string that will belong only to a single document. This field exists to ensure that individual documents stay separate from others and to easily locate/communicate information about a specific document.