covariant

adj

1. (not-comparable)Which preserves the order of morphism composition: formally, which associates each morphism f:X→Y to a morphism F(f):F(X)→F(Y).
2. (not-comparable)Using or relating to covariance.

noun

1. 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.
2. The variety defined by a covariant.