spin structure
lift of the SO(n) frame bundle of an oriented Riemannian manifold into Spin(n), the spin group
en-US/ˈspɪn ˈstɹʌkt͡ʃɚ/
en-GB/ˈspɪn ˈstɹʌkt͡ʃə/
lift of the SO(n) frame bundle of an oriented Riemannian manifold into Spin(n), the spin group