四よつ折おり

noun, noun which may take the genitive case particle 'no'

folding into four; quarto

Refers to folding a sheet of paper into four equal parts, or the resulting size (quarto). Often used in contexts like document preparation, origami, or bookbinding.

• 書しょ類るいを四よつ折おりにして封ふう筒とうに入いれてください。