  We propose many-body order parameters for bulk multipoles in crystalline
systems, which originate from the non-trivial topology of the nested Wilson
loop spectrum. The many-body order parameters are designed to measure
multipolar charge distribution in a crystalline unit cell, and they match the
localized corner charge originating from the multipoles. We provide analytic
arguments and numerical proof for the order parameters. Furthermore, we show
that the many-body order parameters faithfully measure the physical multipole
moments even when the symmetries quantizing multipoles are lost and thus the
nested Wilson loop spectrum does not exactly reproduce the physical multipole
moments.
