Longman Dictionary of Contemporary English - lecture

~1 n 1 a long talk given to a group of people on a particular subject, especially as a method of teaching in universities + on/abou  (a lecture on medieval art) give a lecture  (She's giving a series of lectures on molecular biology.) 2 an act of criticizing someone or warning them about something in a long, serious talk, in a way that they think is unfair or unnecessary + on/abou  (My aunt gave me a long lecture about the dangers of drink.) ~2 v 1 to talk angrily or seriously to someone in order to criticize or warn them, in a way that they think is unfair or unnecessary  (I wish you'd stop lecturing me! | lecture sb about/on)  (Mrs Reed was continually lecturing her children about their behaviour.) 2 to talk to a group of people on a particular subject, especially as a method of teaching at a university