Party

A state (or regional economic integration organization such as the European Union) that agrees to be bound by a treaty and for which the treaty has entered into force. The UNFCCC divides countries into three main groups according to their differing commitments: Annex I Parties (43, including 14 EITs and the EU), Annex II Parties (24, including the EU) and Non-Annex I Parties (see also Annex I/Annex II/Non-Annex I Parties). 49 Parties are LDCs, given special status under the treaty following from their limited capacity to act on and adapt to the effects of climate change. As of 2014, the UNFCC has 196 parties including all member states of the United Nations, Niue, the Cook Islands and the European Union. In addition, the Holy See and Palestine participate as observer states.


Sources:
unfccc.int (general source)
unfccc.int (List of Parties to the UNFCCC and observer states)
Wikipedia.org