Why is papyrus not considered paper made by the modern papermaking process?

Papyrus is not considered paper made by the modern papermaking process because it lacks the fundamental step of complete defibring.1

In modern papermaking, the process begins by separating and wetting cellulose fibres to create a pulp or stock. This pulp is then filtered on a wire screen to form a matted or felted sheet from a water suspension.21

In contrast, the production of papyrus did not involve breaking the plant down into individual fibres. Instead, the ancient method relied on taking thin, longitudinal strips from the pith of the papyrus stem, placing them side by side, and layering them at right angles. These layers were then dampened and pressed together, relying on the plant's natural, gluelike sap to act as an adhesive to cement the strips into a single sheet. Because the structural integrity of the original plant strips remained intact rather than being reconstituted as a matted sheet of fibres, it does not meet the technical definition of paper.132