Its name comes from the old practice of placing a mark on the first (top) page to guide the gatherer.
"Sheet of printed paper that is folded one or more times to become a single unit of several pages in multiples of 4, such as an 8-page, 12-page, 16-page signature. Signatures are collected in their proper sequence (called 'gathering'), bound or sewn, and trimmed to produce the finished publication. Its name comes from the old practice of placing a mark on the first (top) page to guide the gatherer."
"Sheet of printed paper that is folded one or more times to become a single unit of several pages in multiples of 4, such as an 8-page, 12-page, 16-page signature. Signatures are collected in their proper sequence (called 'gathering'), bound or sewn, and trimmed to produce the finished publication. Its name comes from the old practice of placing a mark on the first (top) page to guide the gatherer."