Lagrangian submanifold

If $(M,\omega )$ is a symplectic $2n$-manifold (http://planetmath.org/SymplecticManifold), then a submanifold $L$ is called if it is isotropic, and of dimension $n$. This is the maximal dimension an isotropic submanifold can have, by the non-degeneracy of $\omega$.