majority rule

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A doctrine by which a numerical majority of an organized group holds the power to make decisions binding on all in the group.

from the GNU version of the Collaborative International Dictionary of English.

• noun The rule or doctrine that the numerical majority{2} of an organized group can make decisions binding on the whole group. Contrasted with unanimous consent, or decision by a decree of a single person or small committee forming part of an organization.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A decision rule whereby the decisions of the numerical majority of a group will bind on the whole group.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the doctrine that the numerical majority of an organized group can make decisions binding on the whole group