contravariant in Finnish

(category theory, of a functor) Which reverses the order of morphism composition: formally, which associates each morphism f:X \to Y to a morphism F(f):F(Y) \to F(X).

(algebra) A bihomogeneous polynomial in dual variables of x, y, ... and the coefficients of some homogeneous form in x, y, ... that is invariant under some group of linear transformations.