The word 'ordination' is reserved for
the sacramental act which integrates a man into the order of
bishops, presbyters [priests], or deacons. ... Catholic doctrine
teaches that the degrees of priestly participation (episcopate and
presbyterate) and the degree of service (diaconate) are all three
conferred by a sacramental act called 'ordination,' that is, by the
sacrament of Holy Orders."
Catechism of the Catholic Church, paragraphs 1538 & 1554
will connect you with information about being a diocesan priest in
the Archdiocese of Chicago.