Having two beats, or a multiple of two beats, in each measure. (adjective)
Having two beats in each foot. (adjective)
Examples of word duple
Conductors should mark the changes, and conduct them (beating the half-note, as much as possible); singers need only keep an even quarter-note pulse, whether duple or compound, and follow the natural rhythm and accentuation of the text.
Both musicians relished the dancing hemiola figures in the third movement, shifts of the downbeat between duple and triple groupings, and played with impressive bravura and accuracy.
From a musical perspective, these were melodies written in minor keys, in duple meter, at times in the rhythm of a marche (in most cases, a slow marche), in strophic form.
Certainly, the rhymthic structures are quadruple and duple (with the exception of "Hitler In My Heart" where we are given 5's and 7's), but within those thoroughly square and masculine rhythms, there is a litheness, a suppleness, a winding and breathing, a certain fluidity that is thoroughly feminine.
The primary difference in the Karp transcription (Vol. 2, pg. 206) and the Helmer transcription (pg. 243) is that the former is in triple meter and the latter, duple.