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Theory predicts it near magnetic saturation in several frustrated magnets, but no experiment has measured this hidden pair order directly.","posed_since":"","precise":"In a frustrated J1-J2 magnet with J1 < 0 (candidate $\\mathrm{LiCuVO_4}$ near saturation) or a spin-1 magnet with bound two-magnon states (candidate Na2BaNi(PO4)2), demonstrate quadrupolar order $\\langle S^{+}_{i}S^{+}_{j}\\rangle \\ne 0$ with $\\langle S_{i}\\rangle=0$ using a direct probe (resonant x-ray scattering, NMR lineshape and relaxation, or two-magnon bound-state spectroscopy). An answer is a material and field range with a measured quadrupolar order parameter.","problem_ref":"1c457cb8b21a0742cec6160cde606246e46090526e290aef0775d712aa10a27c","references":"","settled_by":"A measurement of long-range quadrupolar order or a two-magnon condensate together with absence of dipolar order in the same field window.","status_note":"Evidence in $\\mathrm{LiCuVO_4}$ near saturation remains indirect (NMR, magnetization, magnetostriction); condensation of a two-magnon bound state was reported in spin-1 Na2BaNi(PO4)2 (Sheng et al., Research Square preprint 2024) without a direct measurement of the quadrupolar order parameter.","title":"Direct observation of a spin-nematic phase in a 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