  Recent advances in interpreting the most accurate to-date measurement of
atomic parity violation in Cs are reviewed. The inferred nuclear weak charge,
Q_W = - 72.65(28)_expt (36)_theor, agrees with the prediction of the standard
model at 1 sigma level. Further improved interpretation is limited by an
accuracy of solving basic correlation problem of atomic structure. We report on
our progress in solving this problem within the relativistic coupled-cluster
formalism. We include single-, double- and triple- electronic excitations in
the coupled-cluster expansion. Numerical results for energies, electric-dipole
matrix elements, and hyperfine-structure constants of Cs are presented.
