edge title

What is edge title?

edge title meaning in Information Science terminology / glossary / dictionary is:

A title written in ink on one or more edges of the sections of a book, not by the binder but by the owner. This method of marking the outside of a volume was used until the 16th century when books began to be shelved upright with the spine out, instead of flat with one of the edges facing out.

 

reference: ABC-CLIO