Definition of "quarto" []

• The page size obtained by folding a whole sheet into four leaves. (noun)
• A book composed of pages of this size. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "They form six volumes in quarto; and as Basil is the worst, so"
• "Ephorus, in quarto historiarum libro, orbem terrarum inter Scythas,"
• "Latin, Lipsiae, 1766, in quarto, with the learned notes of Kochler and Reiske, and some extracts of geography and natural history from"