  Helioseismology has provided very detailed inferences about rotation of the
solar interior. Within the convection zone the rotation rate roughly shares the
latitudinal variation seen in the surface differential rotation. The transition
to the nearly uniformly rotating radiative interior takes place in a narrow
tachocline, which is likely important to the operation of the solar magnetic
cycle.The convection-zone rotation displays zonal flows, regions of slightly
more rapid and slow rotation, extending over much of the depth of the
convection zone and converging towards the equator as the solar cycle
progresses. In addition, there is some evidence for a quasi-periodic variation
in rotation, with a period of around 1.3 yr, at the equator near the bottom of
the convection zone.
