(Lat.: ‘triple’, ‘threefold’)
Terms used in medieval theory to denote principally (1) three-voiced polyphony. In 13th-century theoretical writing both terms were used as nouns in this sense, or as adjectives in phrases such as ‘organum triplum’ and ‘triplices conductus’ (see Organum and Conductus).
(2) The third voice of a polyphonic composition – an independent voice composed against a tenor and duplum (or motetus). The term ‘triplum’ was thus used in the 13th century with reference to organum and the motet; it remained in use in the 14th century, and can be found also (together with ‘triplex’) in the 15th century, although mostly replaced by terms such as ‘cantus’ and ‘superius’. The English form, ‘treble’, was used in the vernacular early 15th-century treatises on English discant.
(3) ‘Triplex’ is the name given to the highest of the three partbooks of a set in the 16th and 17th centuries (see Partbooks).
(4) Diminution or augmentation by a factor of three (‘tripla’, ‘proportio tripla’) in mensural notation of the 14th century to the 16th (...