  Characterizing genuine quantum resources and determining operational rules
for their manipulation are crucial steps to appraise possibilities and
limitations of quantum technologies. Two such key resources are
nonclassicality, manifested as quantum superposition between reference states
of a single system, and entanglement, capturing quantum correlations among two
or more subsystems. Here we present a general formalism for the conversion of
nonclassicality into multipartite entanglement, showing that a faithful
reversible transformation between the two resources is always possible within a
precise resource-theoretic framework. Specializing to quantum coherence between
the levels of a quantum system as an instance of nonclassicality, we introduce
explicit protocols for such a mapping. We further show that the conversion
relates multilevel coherence and multipartite entanglement not only
qualitatively, but also quantitatively, restricting the amount of entanglement
achievable in the process and in particular yielding an equality between the
two resources when quantified by fidelity-based geometric measures.
