What does quadrilateral mean?
A quadrilateral is a polygon defined by four sides and four vertices. It is one of the basic categories of geometric figure, alongside triangles, pentagons, and hexagons. Its familiar members include squares, rectangles, parallelograms, trapezoids, and rhombi, although a quadrilateral need not have equal sides or equal angles. The term is especially common in geometry, surveying, architecture, cartography, and technical drawing, where the shape of an object or boundary is being classified. In general writing, “quadrilateral” may sound more formal than simply saying “four-sided shape,” but it is useful when the exact number of sides matters. The word comes from Latin elements meaning “four” and “side,” reflecting the figure’s defining feature.
A polygon with four sides and four vertices.
"The student drew a quadrilateral with one pair of parallel sides."
In geometry, this is the standard term for any four-sided polygon, including squares and rectangles.
Having four sides or four corners; four-sided.
"The building's quadrilateral footprint fits neatly within the plot."
This use is less common than the noun and is mainly found in technical or descriptive writing.
The standard plural is “quadrilaterals.”
"The diagram shows several quadrilaterals with different proportions."
From the Latin word for “four-cornered,” the quadrilateral is geometry’s familiar four-sided figure, with squares, rectangles, and rhombi all belonging to the family.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does quadrilateral come from?
The word enters English through Latin quadrilateralis, meaning “four-sided” or “having four corners.” It is built from quadr-, a combining form meaning “four,” and a term related to latus, meaning “side.” The same Latin family includes cognates such as quadrangle, quadrant, and quadrate, all reflecting the idea of four parts or four sides.
Related word forms
How quadrilateral is actually used
In technical geometry, the term is precise and includes quadrilaterals that are not necessarily regular. Outside mathematics, it may sound formal or technical when describing any four-sided outline.
Easily confused with quadrilateral
A quadrilateral is a geometric figure with four sides, whereas a quadrangle traditionally refers to a four-sided courtyard or a group of four people.
A quadrilateral is a four-sided polygon, while a quadrant is one of four equal sections of a circle or coordinate plane.