The Collaborative International Dictionary of English v.0.48:
R'egime \R['e]`gime"\ (r?`zh?m"), n. [F. See Regimen.]
1. Mode or system of rule or management; character of
government, or of the prevailing social system.
I dream . . . of the new r['e]gime which is to come.
2. (Hydraul.) The condition of a river with respect to the
rate of its flow, as measured by the volume of water
passing different cross sections in a given time, uniform
r['e]gime being the condition when the flow is equal and
uniform at all the cross sections.
The ancient r['e]gime, or Ancien r['e]gime [F.], the
former political and social system, as distinguished from
the modern; especially, the political and social system
existing in France before the Revolution of 1789.