Medium shot (MS)

A medium shot (MS) is usually used between a long shot and a close- up shot. It is a camera shot from a medium distance. The picture is mostly from the knees up or the waist up. The medium shot tends to narrow the center of interest for the audience and it shows what you have to see in the picture.
(picture: google images)
http://www.releasing.net/filmmaker/long_medium_close-up_shots.html
http://www.releasing.net/books/33-medium.html
http://arts.endow.gov/about/40th/images/lincoln.jpg