A palimpsest (/ˈpælɪmpsɛst/) is a manuscript page, either from a scroll or a book, from which the text has been scraped or washed off so that the page can be reused for another document. Parchment and other materials for writing or engraving upon were expensive to produce, and in the interest of economy were re-used wherever possible. In colloquial usage, the term palimpsest is also used in architecture, archaeology, and geomorphology, to denote an object made or worked upon for one purpose and later reused for another, for example a monumental brass the reverse blank side of which has been re-engraved.
The word "palimpsest" derives from the Latin , from the Ancient Greek (palímpsēstos, "again"), thus meaning "scraped clean and used again". The Ancient Romans wrote (literally scratched on letters) on wax-coated tablets, which were easily re-smoothed and reused; Cicero's use of the term "palimpsest" confirms such a practice.
Because parchment prepared from animal hides is far more durable than paper or papyrus, most palimpsests known to modern scholars are parchment, which rose in popularity in Western Europe after the 6th century. Where papyrus was in common use, reuse of writing media was less common because papyrus was cheaper and more expendable than costly parchment. Some papyrus palimpsests do survive, and Romans referred to this custom of washing papyrus.