<Enqueue> is used to line up the callers who have placed incoming phone call. <Queue> is the “line” where callers are waiting. Dialing into a <Queue> dequeues a waiting caller by connecting the call.
For example, let’s say you have a customer service hotline. Customers who are calling into your hotline will need to be enqueued in a line until an agent is available to answer their call. To do this you will use the <Enqueue> verb.
Now, you need to connect the support agent to your customers who are waiting. In order to do this, your application will use the <Dial> verb to have the agent call the <Queue>. Each time your agents <Dial> the <Queue>, one of the waiting customers will be dequeued and connected to the agent who initiated the <Dial>.