\begin{definition}[Definition:Hodge Star Operator]
Let $\struct {M,g}$ be an oriented $n$-dimensional Riemannian manifold.
Let $T^* M$ be the cotangent bundle of $M$.
Let $T^k T^*M$ be the space of contravariant $k$-tensors on $T^* M$.
Let $\Lambda^k T^* M$ the subbundle of $T^k T^*M$ consisting of alternating tensors.
Let $\omega, \eta$ be smooth $k$-forms.
Let $\innerprod \cdot \cdot_g$ be the inner product on $k$-forms.
Let $\rd V_g$ be the Riemannian volume form.
Let $\wedge$ denote the wedge product.
'''Hodge star operator''' is a smooth bundle homomorphism $* : \Lambda^k T^* M \to \Lambda^{n - k} T^*M$ such that:
:$\omega \wedge *\eta = \innerprod \omega \eta_g \rd V_g$
{{NamedforDef|William Vallance Douglas Hodge|cat = Hodge}}
\end{definition}