Consisting of or involving two parts or components usually in pairs. Synonyms:double, dual."A double (binary) star" , "Double doors" , "Dual controls for pilot and copilot" , "Duple (or double) time consists of two (or a multiple of two) beats to a measure"
...Duple time did not come into general use until the beginning of the fourteenth century. About the same time, the organum (as it was called) or system of harmonization of Hucbald was discarded, and Johannes ... — Critical & Historical Essays - Lectures delivered at Columbia University • Edward MacDowell
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