A symmetry-preserving continuum approach to meson bound states in quantum field theory, employed elsewhere to describe numerous π- and K-meson electroweak processes, is used to analyze leptonic and semileptonic decays of D(s) mesons. Each semileptonic transition is conventionally characterized by the value of the dominant form factor at t = 0 and the following results are obtained herein: f+Ds→K ( 0 ) = 0.673 ( 40 ) ; f+ D→π+ ( 0 ) = 0.618 ( 31 ) and f+ D→K ( 0 ) = 0.756 (36). Working with the computed t -dependence of these form factors and standard averaged values for | Vcd |, | Vcs|, one arrives at the following predictions for the associated branching fractions: BD+s → K0e+νe = 3.31 ( 33 ) × 10−3, BD0→e+νe = 2.73 ( 22 ) × 10−3, and BD0→K−e+νe = 3.83 ( 28 ) %. Alternatively, using the calculated t -dependence, agreement with contemporary empirical results for these branching fractions requires | Vcd | = 0.221 ( 9 ), | Vus | = 0.953 ( 34 ) . With all D(s) transition form factors in hand, the nature of SU(3)-flavor symmetry breaking in this array of processes can be analysed; and just as in the π−K sector, the magnitude of such effects is found to be determined by the scales associated with emergent mass generation in the Standard Model, not those originating with the Higgs mechanism.