Definitions for "Medium Format"
A film type with a negative that is larger than 35 mm film. The resulting pictures can be used to create quality prints that are much larger than can be done with 35 mm film. Also refers to a camera that uses medium format film.
Normally, a camera taking roll film (typically 120/220 but also 70mm and a range of obsolete roll film sizes), though there are arguably "medium format" cut film sizes such as 21/4x31/4", 21/2x31/2", 6.5x9cm, and possibly even quarter plate (31/4x41/4"). The most usual formats on 120 films are 645 (15-on or 16-on, around 42x56mm), 6x6cm or 21/4 square (12-on, around 56x56mm), 6x7cm (10-on, around 56x70mm) and 6x9cm or 21/4x31/4" (8-on, around 56x84mm), though nominal 6x8cm, 6x12cm, 6x17cm, and even 6x24cm formats also exist.
A larger format than the popular 35mm size, which can provide the image quality necessary for commercial reproduction, using 120, 220 or 70mm film. Various sizes can be shot, the most popular are 6cmx6cm, 6cmx4.5cm and 6cmx7cm. (see 35mm)