What does quadric mean?
A quadric is a geometric or algebraic object defined by an equation of the second degree. The word is used especially for surfaces such as spheres, ellipsoids, paraboloids, and hyperboloids, as well as for quadratic forms associated with these surfaces. In everyday mathematical discussion, “quadratic” may describe any expression or equation involving squared quantities, but “quadric” points more specifically toward a second-degree geometric object or its algebraic description. The term appears in geometry, linear algebra, differential geometry, physics, and engineering, particularly when modeling curved surfaces and curved spacetime. Its usefulness lies in identifying an entire class of objects by the degree of their defining equation, allowing apparently different shapes to be analyzed through shared mathematical methods.
Relating to a geometric surface or algebraic object defined by a second-degree equation.
"The researchers proposed a quadric description of the surface."
Technical mathematical term, especially used in geometry, algebra, physics, and engineering.
A geometric surface or algebraic variety defined by a second-degree equation.
"A quadric can represent an ellipsoid, paraboloid, or hyperboloid."
Usually used in technical mathematical contexts; the plural is “quadrics.”
The plural is used for multiple geometric surfaces or algebraic objects of this type.
"The study compares several quadrics with different curvature properties."
A quadric is the mathematical name for surfaces such as ellipsoids and paraboloids: even when its equation looks complicated, it belongs to the second-degree family.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does quadric come from?
The word “quadric” comes through the combining form quadr-, associated with Latin quadrus, meaning “square” and ultimately “four.” It reflects the fact that the defining equation is quadratic, or of the second degree. The same Latin root appears in words such as “quadratic,” “quadruple,” “quartet,” and “square.”
How quadric is actually used
The term is mainly technical, especially in geometry, algebra, physics, and engineering. It is more specific than the broader term “quadratic” when referring to a geometric surface.
Easily confused with quadric
“Quadratic” generally describes an expression, equation, or function of the second degree, whereas “quadric” more specifically refers to a geometric surface or related algebraic object defined by a second-degree equation.
A quadric is defined by a second-degree equation, while a quartic is defined by an equation of the fourth degree.