When we were kids we called 3-hole-punched, lined paper “foolscap”.

But I never knew why.

Foolscap folio (commonly contracted to foolscap or folio) is paper cut to the size of 8.5 by 13 inches (215.9 mm × 330.2 mm). This was a traditional paper size used in Europe and the Commonwealth, before the adoption of the international standard A4 paper (the most common standard size outside the United States and Canada). Foolscap is a common size for ring binders/lever arch files used to hold A4 paper as it is slightly larger than A4 and offers greater protection to the edge of the pages.

A full foolscap paper sheet is 17 by 13.5 inches (431.8 mm × 342.9 mm) in size, and a folio sheet of any type is half the standard sheet size. Foolscap was named after the fool’s caps and bells watermark commonly used from the fifteenth century onwards on paper of these dimensions] or a subdivision of this into halves, quarters and so on. The earliest example of such paper that is firmly dated was made in Germany in 1479.

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