A spoken lesson or exposition, usually delivered to a group.
During class today the professor delivered an interesting lecture.
(by extension) a class that primarily consists of a (weekly or other regularly held) lecture (as in sense 1) [usually at college or university]
Lecture notes are online.
A berating or scolding.
I really don't want you to give me a lecture about my bad eating habits.
The act of reading.
the lecture of Holy Scripture
To teach (somebody) by giving a speech on a given topic.
The professor lectured to two classes this morning.
To preach, to berate, to scold.
Emily's father lectured her about the importance of being home before midnight.