Book size (6)
'book size' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for quarto that I've seen before include "Book page size" , "Ten-by-eight inch paper" , "Publishing term, four leaves are formed from one sheet" , "Twice-folded paper size" , "Book size resulting in folding one sheet four times" .)
'book size' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for octavo that I've seen before include "Common book size" , "Size of a book, pages are made by folding a sheet of paper three times to form eight leaves (6)" , "An eight-leaved book or page" , "Size of book page" .)
(Other definitions for volume that I've seen before include "Gross < sound" , "Amount of three-dimensional space occupied" , "Book - sound level" , "size" , "Cubic capacity" .)
'book size' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for folio that I've seen before include "Book made of folded sheets" , "Book; wrapper for loose papers" , "Sheet of paper folded to make two book leaves" , "Two-leaf sheet" , "eaf" .)
(Other definitions for duodecimo that I've seen before include "scale of work?" , "Size of book" , "small book" .)