The English word "paper" is etymologically derived from papyrus, Ancient Greek for the Cyperus papyrus plant. Papyrus is a thick, paper-like material produced from the pith of the Cyperus papyrus plant which was used in ancient Egypt and other Mediterranean societies for writing. When used in scrolls, repeated rolling and unrolling causes the strips to come apart again, typically along vertical lines. This effect can be seen in many ancient papyrus documents.