leciono

Leciono is the unit of teaching, whether in a classroom or in a textbook, and Zamenhof's own Fundamento is organised into numbered lecionoj, so the word has been part of learning Esperanto from the first page. The figurative sense works too: tio estu leciono por vi scolds exactly like its English equivalent. Keep it apart from kurso, the whole course, and from instruo, the teaching itself. To take lessons is preni lecionojn; to give them, doni lecionojn.