Answer .
A seminar is, generally, a form of academic instruction, either at a university or offered by a commercial or professional organization. It has the function of
…bringing together small groups for recurring meetings, focusing each time on some particular subject, in which everyone present is requested to actively participate. This is often accomplished through an ongoing Socratic dialogue with a seminar leader or instructor, or through a more formal presentation of research. Normally, participants must not be beginners in the field under discussion (at a university, seminar classes are generally reserved for upper-year students)..
Taken from wikipedia online.
There are individuals who have a great deal of expertise in a particular area that do give seminars. Some make a living at it. So, seminars are not specific to just colleges and universities. Organizations of all types may bring in individuals to either head/lead seminars or speak at them. Once again, this individual is usually an expert within a specific field. (MORE)