What is the meaning of lesson?

noun

• A unit of instruction.
  • usage: "he took driving lessons"
• Punishment intended as a warning to others.
  • usage: "they decided to make an example of him"
  • synonyms: example, deterrent example, object lesson
• The significance of a story or event.
  • usage: "the moral of the story is to love thy neighbor"
  • synonyms: moral
• A task assigned for individual study.
  • usage: "he did the lesson for today"