Longman Dictionary of Contemporary English - lesson

~ n 1 »LEARNING A SKILL« a period of time in which someone is taught a particular skill, for example how to play a musical instrument or drive a car  (piano lessons | take lessons)  (She's started taking driving lessons.) + on/in  (lessons in social etiquette) 2 »IN SCHOOL« BrE a period of time in which students in a school are taught a particular subject; class1 (3) AmE  (What did you do last lesson? | boring Maths lessons) + in/on  (lessons on eight different subjects every week) 3 »WARNING« an experience, especially an unpleasant one, that makes you more careful in the future  (Pearl Harbor was a painful lesson for the US.) 4 let that be a lesson to you spoken used to warn someone that they must be more careful in order to avoid the same bad experience happening to them again 5 »BOOK« a part of a book that is used for learning a particular subject, especially in school  (Turn to lesson 25.) 6 »CHURCH« a short piece that is read from the Bible during a religious ceremony  (- see also learn your lesson learn (7), teach sb a lesson teach (6))