The UNFCCC stands for the United Nations Framework Convention on Climate Change. The Convention entered into force on 21 March 1994. Today, membership of the Convention, which forms the basis of the 2015 Paris Agreement, is almost universal (198 «Parties»). Its overriding objective is to limit as far as possible the increase in global average temperature to 1.5°C above pre-industrial levels. The UNFCCC is also the founding treaty of the 1997 Kyoto Protocol.
The ultimate objective of the three UNFCCC agreements is to «stabilise greenhouse gas concentrations at a level that would prevent dangerous anthropogenic interference with the climate system (...), within a timeframe sufficient to allow ecosystems to adapt naturally to climate change, and to enable economic development to proceed in a sustainable manner».
The 198 countries that have ratified the Convention are known as Parties.
More information on the UNFCCC, here on the website.