Consensus has two common meanings. One is a general agreement among the members of a given group or community, each of which exercises some discretion in decision making and follow-up action. The other is as a theory and practice of getting such agreements.

Achieving consensus requires serious treatment of every group member's considered opinion. Once a decision is made it is important to trust in members' discretion in follow-up action. In the ideal case, those who wish to take up some action want to hear those who oppose it, because they count on the fact that the ensuing debate will improve the consensus. In theory, action without resolution of considered opposition will be rare and done with attention to minimize damage to relationships.

A close equivalent phrase might be the "collective opinion" of a group, keeping in mind that a high degree of variation is still possible among individuals, and certainly if there must be individual commitment to follow up the decision with action, this variation remains important. There is considerable debate and research into both collective intelligence and consensus decision-making.

This article focuses strictly on the idea of consensus in the abstract, not on the implications of consensus for politics or economics, where follow-up action is required.

Consensus usually involves collaboration, rather than compromise. Instead of one opinion being adopted by a plurality, stakeholders are brought together until a convergent decision is developed. If this is done in a purely mechanical way it can result in simple trading—we'll sacrifice this if you'll sacrifice that. Genuine consensus typically requires more focus on developing the relationships among stakeholders, so that they work together to achieve agreements based on willing consent.