Borrowed from Middle French -, from Old French -, from Medieval Latin - or Late Latin rectangulum, from Latin rectus + angulus ("an angle").

• IPA: /ˈrɛktæŋɡl̩/

rectangle (plural rectangles)

1. (geometry) Any quadrilateral having opposing sides parallel and four right angles.

   Hypernyms: polygon

   Hyponym: square

   Coordinate terms: circle, ellipse, triangle, trapezoid, rhombus

2. (nontechnical) Such a quadrilateral that is oblong (longer than it is wide): one that is not regular (equilateral), that is, any except a square.

   Hypernyms: shape, polygon

   Coordinate terms: square, circle, oval, ellipse, triangle, trapezoid, rhombus, lozenge, diamond

3. (archaic) A right angle.
   • 1884, A Square [pseudonym; Edwin A. Abbott], Flatland […] , London: Seeley & Co., [S%3Aen%3AFlatland+%28first+edition%29%2FThis+World Part I: This World, § 12.— Of the Doctrine of our Priests], page 46 ↗:

     For why should you praise, for example, the integrity of a Square who faithfully defends the interests of his client, when you ought in reality rather to admire the exact precision of his Rectangles?

4. (archaic) The product of two quantities.
   • 1728, E[phraim] Chambers, “Product”, in Cyclopædia: Or, An Universal Dictionary of Arts and Sciences; […] In Two Volumes, volumes II (I–Z), London: […] James and John Knapton [et al.], →OCLC ↗, page 886 ↗, column 1:

     In Lines it [the product] is always (and ſometimes in Numbers) call'd the Rectangle between the two Lines, multiply'd by one another.

• French: rectangle
• German: Rechteck, Karree, Orthogon
• Italian: rettangolo
• Portuguese: rectângulo (Portugal), retângulo (Brazil)
• Russian: прямоуго́льник
• Spanish: rectángulo

rectangle (not comparable)

1. (archaic) Right-angled.

   a rectangle triangle