Rectangular and Quarto

adjective

• Having four right angles.
  • usage: "a rectangular figure twice as long as it is wide"
• Having a set of mutually perpendicular axes; meeting at right angles.
  • usage: "wind and sea may displace the ship's center of gravity along three orthogonal axes"; "a rectangular Cartesian coordinate system"
  • synonyms: orthogonal

(a.) Right-angled; having one or more angles of ninety degrees.

noun

• The size of a book whose pages are made by folding a sheet of paper twice to form four leaves.
  • synonyms: 4to

• (a.) Having four leaves to the sheet; of the form or size of a quarto.
• (n.) Originally, a book of the size of the fourth of sheet of printing paper; a size leaves; in present usage, a book of a square or nearly square form, and usually of large size.