Webster's Revised Unabridged Dictionary · 1913

Irreducible

Irreducible , adjective

1.
Incapable of being reduced, or brought into a different state; incapable of restoration to its proper or normal condition; as, an irreducible hernia.
2.
(Mathematics) Incapable of being reduced to a simpler form of expression; as, an irreducible formula.
Collocations (1)
Irreducible case (Algebra) , a particular case in the solution of a cubic equation, in which the formula commonly employed contains an imaginary quantity, and therefore fails in its application.