An equation in which the highest power of an unknown quantity is a square.

synonym: quadratic equation.

Dutch: tweedegraadsvergelijking

A polynomial of the second degree.

synonym: quadratic polynomial.

Polish: trójmian kwadratowy

Involving the second and no higher power of a quantity or degree.

Roget 95: four; quaternary, quaternal^†; quadratic; quartile; tetract^†, tetractic^†, tetractinal^†; tetrad, tetragonal; square, quadrate.   

Polish: kwadratowy