Definitions of lecture:

• noun:   teaching by giving a discourse on some subject (typically to a class)
• noun:   a lengthy rebuke

  Example: "A good lecture was my father's idea of discipline"

• noun:   a speech that is open to the public

  Example: "He attended a lecture on telecommunications"

• verb:   deliver a lecture or talk

  Example: "Did you ever lecture at Harvard?"

• verb:   censure severely or angrily