Definition of qualified majority in US English:

qualified majority

noun

Politics Business
  • A specified proportion above a simple majority, as a requirement for ratification in a voting system; specifically (in the Council of Ministers in the European Union) a majority in a system of weighted voting, in which each member nation has a certain number of votes according to its status, and the required majority is calculated to ensure a proposal may not be blocked by one powerful nation; frequently attributive, as "qualified majority voting", etc.

Origin

Early 20th century.