Catchword

A catchword is a word placed at the foot of a handwritten or printed page that is meant to be bound along with other pages in a book.

It was meant to help the bookbinder or printer make sure that the leaves were bound in the right order or that the pages were set up in the press in the right order.

[citation needed] Catchwords appear in some medieval manuscripts, and appear again in printed books late in the fifteenth century.

The practice became widespread in the mid sixteenth century, and prevailed until the arrival of industrial printing techniques late in the eighteenth century.

Theodore Low Devinne's 1901 guide on Correct Composition had this to say: For more than three centuries printers of books appended at the foot of every page the first word or syllable of the next page.

The catchword (in this case the last three letters " dos " of a divided word) is at the bottom of the page
The first page of the Babylonian Talmud ( Tractate Berachot , folio 2a). The catchword "דילמא" is found at the bottom of the Talmud text (center), and the commentaries of Rashi (center left) and the Tosafot (center right) as the word will begin each text on the next page, 2b.