  Given the multitude of applications of vector vortex beams there is a need
for robust tools to measure them. Here we exploit the non-separability of such
beams, akin to entanglement of quantum states, to apply tools traditionally
associated with quantum measurements to these classical fields. We apply three
measures of non-separability: a Bell inequality, a concurrence, and an
entanglement entropy to define the "vectorness" of such beams. In addition to
providing novel tools for the analysis of vector beams, we also introduce the
concept of classical entanglement to explain why these tools are appropriate in
the first place.
