In traditional bookbinding, these assembled folios trimmed and curved were called “codex” in order to differentiate it from the “case” which we now know as “hard cover”. Binding the codex was clearly a different procedure from binding the “case”. This terminology, still in use some 50 or 60 years ago, has been nearly abandoned. Some commercial bookbinders may refer to the cover and the inside of the book instead, but a few others, attached to their traditions, still use the terms “codex” and “case”.
Codex - Wikipedia, the free encyclopedia
how quaint.
