class action suit Civil lawsuit in which a group files a suit on behalf of a larger number of citizens who allege similar damages but who need not be listed and represented individually. Compare civil suit.

common law Body of unwritten rules and principles derived from thousands of past legal decisions. It is based on evaluation of what is reasonable behavior in attempting to balance competing social interests. Compare statutory law.

defendant The individual, group of individuals, corporation, or government agency being charged in a lawsuit. Compare plaintiff. 

democracy Government by the people through their elected officials and appointed representatives. In a constitutional democracy, a constitution provides the basis of government authority and puts restraints on government power through free elections and freely expressed public opinion. 

Environmental justice Fair treatment and meaningful involvement of all people regardless of race, color, sex, national origin, or income with respect to the development, implementation, and enforcement of environmental laws, regulations, and policies. 

plaintiff The individual, group of individuals, corporation, or government agency bringing the charges in a lawsuit. Compare defendant. 

politics Process through which individuals and groups try to influence or control government policies and actions that affect the local, state, national, and international communities. 

Precautionary principle When there is scientific uncertainty about potentially serious harm from chemicals or technologies, decision makers should act to prevent harm to humans and the environment. See pollution prevention.

Prior appropriation Legal principle by which the first user of water from a stream establishes a legal right to continued use of the amount originally withdrawn. Compare riparian rights.

riparian rights System of water law that gives anyone whose land adjoins a flowing stream the right to use water from the stream, as long as some is left for downstream users. Compare prior appropriation.

statutory law Law developed and passed by legislative bodies such as federal and state governments. Compare common law.