lesson (n.)

early 13c., "a reading aloud from the Bible," also "something to be learned by a student," from Old French leçon, from Latin lectionem (nominative lectio) "a reading," noun of action from past participle stem of legere "to read," from PIE root *leg- (1) "to collect, gather," with derivatives meaning "to speak (to 'pick out words')." Transferred sense of "an occurrence from which something can be learned" is from 1580s.