a book, pamphlet
, etc. having (a specified number of) leaves as a result
of the folding of a sheet of paper a given
number of times
12mo, duodecimo, or twelvemo
Webster’s New World College Dictionary, 4th Edition. Copyright © 2010 by
Houghton Mifflin Harcourt. All rights reserved.
Word origin of '-mo'< ending of L abl. forms of ordinals, after prep. in, as in duodecimo (< duodecimus, twelfth)