  Charge-ordered ground states permeate the phenomenology of 3d-based
transition metal oxides, and more generally represent a distinctive hallmark of
strongly-correlated states of matter. The recent discovery of charge order in
various cuprate families fueled new interest into the role played by this
incipient broken symmetry within the complex phase diagram of high-Tc
superconductors. Here we use resonant X-ray scattering to resolve the main
characteristics of the charge-modulated state in two cuprate families: Bi2201
and YBCO. We detect no signatures of spatial modulations along the nodal
direction in Bi2201, thus clarifying the inter-unit-cell momentum-structure of
charge order. We also resolve the intra-unit-cell symmetry of the charge
ordered state, which is revealed to be best represented by a bond-order with
modulated charges on the O-2p orbitals and a prominent d-wave character. These
results provide insights on the microscopic description of charge order in
cuprates, and on its origin and interplay with superconductivity.
