Object Oriented means to Perl (not PERL, by the way) mostly that you have a blessed reference (object) or a string (class), on which you can call a method. A module on CPAN certainly is not the central point, as packages can contain methods for objects, but they can also export normal functions. CPAN has nothing to do with that.

• Is Perl Truly an Object Oriented Language?
• Object-oriented interface for binmode
• perspective and object-disorientation
• Tutorial: Introduction to Object-Oriented Programming - this is more about the usage in Perl