A lecture is a lesson delivered in an artistic format.
To give an effective lecture, the instructor needs to show his students the dots to be connected, connect them and then disconnect them so they can then reconnect them on their own.
The artistry of delivering a good lecture lies in the presentation of the material. When presented with energy and gusto in graspable terms, the dots can easily be reconnected.
Every lecture builds on the previous one, creating a pyramid of knowledge.