Learn how to say Quartos correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word quarto:
noun (plural quartos)
[mass noun] Printing
a size of book page resulting from folding each printed sheet into four leaves (eight pages).
[count noun] a book of quarto size.
a size of writing paper, 10 in. × 8 in. (254 × 203 mm).
late 16th century: from Latin (in) quarto ‘(in) the fourth (of a sheet)’, ablative of quartus ‘fourth’