n (pl ~s)
(a) (abbrs 缩写 4to, qto) size of page made by folding a standard sheet of paper twice to form eight pages 四开（标准纸张摺 两次而成八页的大小）.
(b) book made of these folded sheets 四开本
*the first quarto of `Hamlet' 《哈姆雷特》的第一种四开本
* [attrib 作定语] Quarto volumes are too large to fit on this shelf. 这架子上放不下四开本的书.
[Date: 1500-1600; Language: Latin;Origin: quartus; QUARTER1]
the size of paper made by folding a normal large sheet of paper twice to produce four sheets