PCO is an abbreviation that can stand for 76 different meanings, such as Proanthocyanidin, Professional Conference Organizer, or Poly Cystic Ovarian Syndrome. See the full list of definitions and categories of PCO on AcronymFinder.com. STD full form is Subscriber Trunk Dialling ISD full form is International Subscriber Dialling PCO full form is Public Call Office The terms STD ISD PCO are used in the telephone system. They allow subscribers to dial trunk calls without operator assistance through trunk lines. Polycystic ovaries, hormone imbalance and irregular periods are telltale signs and symptoms of polycystic ovary syndrome. Find out about treatments. In this article, we will learn about the PCO full form. Public Call office is the full form of PCO. Get information about its history, operation, features, importance, pros, and cons.