Patent Cooperation Treaty

An international treaty that enables an applicant to file a single patent application (referred to as a PCT or international patent application) which can be used to obtain patents in each of the countries that are signatories to the treaty (also referred to as contracting states).  There are currently 158 contracting states to the PCT, including most countries in which patent protection is commonly sought. 

It should be noted that although the PCT enables a single patent application to be filed initially, that application will ultimately need to be forwarded to (or "entered into") the patent office(s) of each territory for which patent protection is ultimately sought.  Each patent office will then independently assess the application against their own patentability requirements to assess whether a patent should be granted for that territory. 

One of the main benefits of the PCT is that it enables the decision of which countries to pursue protection in (and some of the cost of doing so) to be deferred.