lesson

1. A section of learning or teaching into which a wider learning content is divided.

   In our school a typical working week consists of around twenty lessons and ten hours of related laboratory work.

2. A learning task assigned to a student; homework.
3. Something learned or to be learned.

   Nature has many lessons to teach to us.

4. Something that serves as a warning or encouragement.

   I hope this accident taught you a lesson!

5. A section of the Bible or other religious text read as part of a divine service.

   Here endeth the first lesson.

6. A severe lecture; reproof; rebuke; warning.
7. An exercise; a composition serving an educational purpose; a study.

verb

To give a lesson to; to teach.