Questions concerning giving and attending small but organized presentations of scientific material, often given to an audience within a single academic department. Seminars might occur at several levels. A research seminar will discuss recent results. A course seminar will likely have students prepare and present course material.
The term is used in two senses. The first is a grouping of professionals who gather to discuss some research topic among themselves. They may be working on separate but related ideas and are looking for synergy. In a given session, one presenter may talk about recent results, or the lack of results, looking for ideas.
The second use of the term is for a course in which each student is required to prepare and present some topic(s). The topics might be very advanced (research level) or not. The idea here is to give students the opportunity to prepare material and present it in a relative safe place, with feedback provided by the professor.