A lecture is an oral presentation intended to present information or teach people about a particular subject, for example by a university or college teacher. Lectures are used to convey critical information, history, background, theories and equations. A politician’s speech, a minister’s sermon, or even a businessman’s sales presentation may be similar in form to a lecture. Usually the lecturer will stand at the front of the room and recite information relevant to the lecture’s content.
Though lectures are much criticised as a teaching method, universities have not yet found practical alternative teaching methods for the large majority of their courses. Critics point out that lecturing is mainly a one-way method of communication that does not involve significant audience participation. Therefore, lecturing is often contrasted to active learning. Lectures delivered by talented speakers can be highly stimulating; at the very least, lectures have survived in academia as a quick, cheap and efficient way of introducing large numbers of students to a particular field of study.
Lectures have a significant role outside the classroom, as well. Academic and scientific awards routinely include a lecture as part of the honor, and academic conferences often center around "keynote addresses", i.e., lectures. The public lecture has a long history in the sciences and in social movements. Union halls, for instance, historically have hosted numerous free and public lectures on a wide variety of matters. Similarly, churches, community centers, libraries, museums, and other organizations have hosted lectures in furtherance of their missions or their constituents’ interests.