Definition of quadratic in US English:



  • Involving the second and no higher power of an unknown quantity or variable.

    ‘a quadratic equation’
    • ‘Find the 2 roots and a continued fraction for a root of these quadratic equations.’
    • ‘If f = 0, then the quartic in y is actually a quadratic equation in the variable y 2.’
    • ‘Smith also extended Gauss's theorem on real quadratic forms to complex quadratic forms.’
    • ‘In 1826 Cauchy, in the context of quadratic forms in n variables, used the term ‘tableau’ for the matrix of coefficients.’
    • ‘He was able to use his methods to prove many results in the theory of quadratic forms and number theory.’


  • A quadratic equation.

    • ‘For that matter quadratics aren't all that tough.’
    • ‘The sparseness of the quadratics is what is important here.’
    • ‘Historically, imaginary numbers first came to light when trying to solve cubic equations, rather than quadratics.’
    • ‘The thought that quadratics are now seen as ‘high brow’ really does, once again, make me despair.’
    • ‘This is certainly possible and the Babylonians' understanding of quadratics adds some weight to the claim.’


Mid 17th century: from French quadratique or modern Latin quadraticus, from quadratus ‘made square’, past participle of quadrare (see quadrate).