noun

1. something to be learned; specif.,
   1. an exercise or assignment that a student is to prepare or learn within a given time; unit of instruction
   2. the instruction given during one class or instruction period
   3. something that needs to be learned (or the event through which it is learned) for the sake of one's safety, well-being, etc.
   4. course of instruction music lessons
2. a selection, as of Scripture, forming part of a religious service; lection
3. a rebuke; reproof

Etymology: ME lessoun < OFr leçon < L lectio, a reading, hence text, lesson < pp. of legere, to read: see logic

transitive verb

1. to give a lesson to
2. to rebuke; reprove