The substance which constitutes the essential part of the solid framework of plants, of ordinary wood, cotton, linen, paper, etc. It is also found to a slight extent in certain animals, as the tunicates. It is a carbohydrate, (C6H10O5)n
, isomeric with starch, and is convertible into starches and sugars by the action of heat and acids. When pure, it is a white amorphous mass. See Starch
. [1913 Webster
"Unsized, well bleached linen paper is merely pure cellulose."