In the United Nations, COP stands for Conference of Parties, that is, the governing body of a Convention.
Conventions with a COP include:
COP 21 was the Climate Change Conference held in Paris in November/December 2015. COP stands for "Conference of Parties" and this was the 21st meeting of the UNFCCC (United Nations Framework Convention on Climate Change).
I hope you mean 'What do the initials 'UN' mean - United Nations.
United Nations Space Command.
United Nations
The letters in "cop" stand for "Constable on Patrol." It is a term used to refer to a police officer, especially in the United States.
It is usually taken to mean United Nations.
United nations
I think you mean UNICEF. It stands for the United Nations Children's Fund.
United Nations Special Command
United Nations
The acronym for the (U)nited (N)ations is "UN".
United Nations Space Command