"Parameter: : a rule or limit that controls what something is or how something should be done."-Merriam Webster.

[A "rule" is not the same as a "limit." But the definition of  "parameter" includes both, or either in the conjunctive. It is reasonably clear from context that Parameters uses parameter as meaning "a rule...that controls what something is or how something should be done." We will then substitute "rule" wherever Parameters uses parameters.

-"Rules for a Joint Comprehensive Plan of Action." 

-"Below...key rules."  These were decided."] Pause here for the article in the next post. 

Parameters for a Joint Comprehensive Plan of Action regarding
the Islamic Republic of Iran’s Nuclear Program

Below are the key parameters of a Joint Comprehensive Plan of Action (JCPOA) regarding the
Islamic Republic of Iran’s nuclear program that were decided in Lausanne, Switzerland. These
elements form the foundation upon which the final text of the JCPOA will be written between
now and June 30, and reflect the significant progress that has been made in discussions between
the P5+1, the European Union, and Iran. Important implementation details are still subject to
negotiation, and nothing is agreed until everything is agreed. We will work to conclude the
JCPOA based on these parameters over the coming months.