What does didactic mean?

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From our dictionary:

di•dac•tic

Pronunciation: (dI-dak'tik), [key]
adj.
1. intended for instruction; instructive: didactic poetry.
2. inclined to teach or lecture others too much: a boring, didactic speaker.
3. teaching or intending to teach a moral lesson.
4. didactics, (used with a sing. v.) the art or science of teaching. Also,di•dac'ti•cal.