Gutter language

David Perrell writes:

 > Gutter:
 > The inside margin of the pages in a bound book.
 >         Preparing Art for Printing
 >         Bernard Stone and Arthur Eckstein
 >         Van Nostrand Reinhold Company
 >         (c) 1965 Litton Educational Publishing, Inc.

Gutter: (1) the gutter margin (2) the space between columns of type,
as in table, an index, two-column text format etc.

Glossary of Typesetting Terms 
University of Chicago Press