  A three-dimensional closed orientable orbifold (with no bad suborbifolds) is
known to have a geometric decomposition from work of Perelman along with
earlier work of Boileau-Leeb-Porti and Cooper-Hodgson-Kerckhoff. We give a new,
logically independent, unified proof of the geometrization of orbifolds, using
Ricci flow. Along the way we develop some tools for the geometry of orbifolds
that may be of independent interest.
