According to PRSA (Public Relations Society of America):
Public relations is more than managing the flow of information between an organization and its publics. It is a communications discipline that engages and informs key audiences, builds important relationships and brings vital information back into an organization for analysis and action. It has real, measurable impact on the achievement of strategic organizational goals.
Public relations and publicity are not synonymous; publicity is a small subset and specialized discipline within public relations, often practiced by dedicated firms who may or may not possess broader strategic communications capabilities.
Public relations professionals have a special obligation to practice their craft ethically, with the highest standards of truth, accuracy, fairness and responsibility to the public. The PRSA Code of Ethics provides a practical set of standards to follow in this regard.