A shutter whose blades operate between two elements of the lens. Most medium format cameras like the Hasselblad have one family of lens with shuttle and another without. Most lenses in this family have a smaller maximum aperture than the other family.
Found on
http://www.rodsmith.org.uk/photographic%20glossary/rods%20photographic%20gl
Close to the diaphragm, inside the lens are metal blades which spring open and then close when the camera is fired, this exposes the film. (see Focal plane shutter)
Found on
https://www.encyclo.co.uk/local/20176
No exact match found.
