Definition of covariant:
(adj) :
(object-oriented programming) Using or relating to covariance.
(adj) :
(category theory, of a functor) Which preserves the order of morphism composition: formally, which associates each morphism f:X→Y to a morphism F(f):F(X)→F(Y).
(n) :
(algebra) A bihomogeneous polynomial in x, y, ... and the coefficients of some homogeneous form in x, y, ... that is invariant under some group of linear transformations.
(n) :
(algebra) The variety defined by a covariant.