  We present our new measurement of the cross-section for charm dimuon
production in neutrino-iron interactions based upon the full statistics
collected by the NOMAD experiment. After background subtraction we observe
15,344 charm dimuon events, providing the largest sample currently available.
The analysis exploits the large inclusive charged current sample - about
$9\times 10^6$ events after all analysis cuts - and the high resolution NOMAD
detector to constrain the total systematic uncertainty on the ratio of charm
dimuon to inclusive Charged Current (CC) cross-sections to $\sim 2%$. We also
perform a fit to the NOMAD data to extract the charm production parameters and
the strange quark sea content of the nucleon within the NLO QCD approximation.
We obtain a value of $m_c(m_c)=1.159\pm0.075$ GeV/c$^2$ for the running mass of
the charm quark in the $\bar{\rm MS}$ scheme and a strange quark sea
suppression factor of $\kappa_s = 0.591 \pm 0.019$ at $Q^2=20$ GeV$^2$/c$^2$.
