Lesson (noun)

1. An amount of teaching given to one person or group.
2. A period of time during which teaching takes place.
3. A piece of information or an instruction that can be learned from an experience or an event.

Origin:

Middle english: from old french leçon, from latin lectio(n-), from legere "read".

Examples:

1. He learned a valuable lesson from the experience.
2. She taught the lesson to the class.
3. The lesson was about history.
4. He had a lesson with his piano teacher.
5. The lesson was too easy for the class.