Pan / Oversized Cel (大判 セル画)

Pan or oversized cels are larger-than-normal cels which are used for a panning effect. "Pan" is short for "panoramic" and refers to how the camera has to pan/travel across the frame to reveal more of the image.  Pan cels can be horizontally, vertically, and sometimes even diagonally long. The camera can also do a zoom-in or zoom-out of an oversized cel. The sizes of a pan cel vary greatly, but are all larger than a normal cel.

Pan Cel - Horizontal

Horizontal pan cels refer to cels where the camera moves right to left or left to right. These cels are wider than they are tall.

Pan Cel - Vertical

With Vertical Pan Cels, the camera takes a picture using the same cel (or multiple pan cels) while moving  up or down after each shot. When each of these shots is combined, it creates a panning motion in one direction.

A pan cel of Misato from End of Evangelion. In this shot, several pan cels are used to create a breathing effect during the pan. The right-hand side shows the section of each shot that is in frame.

Pan Cel - Diagonal

Diagonal pan cel from Metal Armor Dragonar ( image taken from Yahoo Japan Auctions)