discriminant
Pronunciation: /dɪˈskrɪmɪnənt/
noun
- a distinguishing feature or characteristic: anaemia is commonly present in patients with both conditions, and is therefore not a helpful discriminant
- Mathematics a function of the coefficients of a polynomial equation whose value gives information about the roots of the polynomial. See also discriminant function.

Origin:
mid 19th century (in the sense 'showing discernment'): from Latin discriminant- 'distinguishing between', from the verb discriminare (see discriminate)