Alternatim

Alternatim refers to a technique of liturgical musical performance, especially in relationship to the Organ Mass. A specific part of the ordinary of the Mass (such as the Kyrie) would be divided into versets. Each verset would be performed antiphonally by two groups of singers, giving rise to polyphonic settings of half of the text. One of these g...
Found on http://en.wikipedia.org/wiki/Alternatim

alternatim

alternately
Found on http://phrontistery.info/a.html
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