Definition

1. Noun:
   • A quadrilateral with four right angles: A "rectangle" is a flat, closed shape with four straight sides. Its defining characteristic is that all four of its interior angles are exactly 90 degrees (right angles).
   • A specific type of parallelogram: A rectangle is a special case of a parallelogram where the angles are right angles. Consequently, its opposite sides are equal in length and parallel to each other.

Examples of Usage

• Noun:
  • The screen of most smartphones is a rectangle.
  • She drew a perfect rectangle on the whiteboard.
  • The area of a rectangle is calculated by multiplying its length by its width.

Advanced Usage

• Mathematical Context: In geometry, a rectangle is defined by the properties of its sides (equal opposite sides) and angles (four right angles). A square is a special type of rectangle where all four sides are of equal length.
  • While all squares are rectangles, not all rectangles are squares.

Variants and Related Words

• Rectangular (adj): Having the shape of a rectangle.
  • The room was large and rectangular.

Synonyms

• Oblong: Often used to describe a rectangle that is longer than it is wide. (Note: In strict geometry, "oblong" is not a technical term, but in common usage it describes an elongated rectangle.)
• Quadrilateral: A general term for any four-sided polygon. A rectangle is a specific type of quadrilateral.

Noun

1. a parallelogram with four right angles