olemus
(1) algebras:
polünoomvõrrandi juurte arvu ja iseloomu näitav funktsioon polünoomi kordajaist
Wiktionary:
1 (algebra) an expression that gives information about the roots of a polynomial

https://en.wikipedia.org/wiki/Discriminant

(2) üldisemalt (more generally)
Merriam-Webster:
: a mathematical expression providing a criterion for the behavior of another more complicated expression, relation, or set of relations