The azimuthal anisotropy coefficient v 2 of prompt D 0 , D + , D * + , and D + s mesons was measured in midcentral (30%–50% centrality class) Pb-Pb collisions at a center-of-mass energy per nucleon pair √ s N N = 5.02     TeV , with the ALICE detector at the LHC. The D mesons were reconstructed via their hadronic decays at midrapidity, | y | < 0.8 , in the transverse momentum interval 1 < p T < 24     GeV / c . The measured D -meson v 2 has similar values as that of charged pions. The D + s

v 2 , measured for the first time, is found to be compatible with that of nonstrange D mesons. The measurements are compared with theoretical calculations of charm-quark transport in a hydrodynamically expanding medium and have the potential to constrain medium parameters.