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Standing Ovation from WikiPedia:

A standing ovation is a form of applause where members of a seated audience stand up while applauding. This is done on special occasions by an audience to show their approval and is done after extraordinary performances of particularly high acclaim. In Ancient Rome returning military commanders whose victories exceeded the standards of a triumph were celebrated with an ovation, from the Latin ovo, "I rejoice". The word's use in English to refer to sustained applause dates from at least 1831.

Standing ovations are considered to be a special honour. Often it is used at the entrance or departure of a speaker or performer, where the audience members will continue the ovation until the ovated person leaves or begins their speech. Usually, when a critical mass of a small fraction of the audience stands up (perhaps one-fifth), the entire audience becomes compelled to stand as well.

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