A sheet or sail at the head or bow of a ship; also, in printing, the first sheet of paper in a bound book.
From 'head' (front, primary) and 'sheet' (a piece of thin material, from Old English 'scēte'). This term has both nautical and printing applications.
In bookbinding, the headsheet (called an endsheet or flyleaf) protects the book's binding—if you've ever opened a beautiful old book and seen decorative paper at the front, that's the headsheet showing off the bookbinder's craft.
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