"Jumbo Xerox" refer to photocopies or printouts made on paper that is larger than the standard or commonly used sizes, such as A3 or larger. These copies are generally bigger than the standard letter or legal paper sizes (A4 and 8.5 x 14 inches, respectively).
Jumbo Xerox are used for various purposes, including making posters, banners, large diagrams, architectural drawings, and other materials that require bigger printing or display sizes. They are suitable for when the content needs to be more visible and impactful, such as in presentations, advertisements, or visual aids for larger audiences.
Common larger paper sizes for jumbo copies might include:

A3: 11.7 x 16.5 inches or 297 x 420 mm

A2: 16.5 x 23.4 inches or 420 x 594 mm

A1: 23.4 x 33.1 inches or 594 x 841 mm

A0: 33.1 x 46.8 inches or 841 x 1189 mm