in music, a 13th-century polyphonic genre featuring two strictly measured parts: notable examples are the descant sections based on the Gregorian chant melisma (several notes to a syllable), which in the organa of the Notre-Dame school alternated with sections featuring coloratura-like passages in relatively free rhythm above a slower-moving cantus firmus.

Clausulae early gained independent status as untexted “substitute” compositions. The first noted composer of such “substitute” clausulae was Pérotin, the successor of Léonin, whose name is forever associated with the two-part organa of the Parisian School. The motet, of only slightly later origin, was in essence a texted clausula. In the clausula the late-medieval, dance-influenced system of rhythmic modes found its first systematic application.

in Greek and Latin rhetoric, the rhythmic close to a sentence or clause, or a terminal cadence. The clausula is especially important in ancient and medieval Latin prose rhythm; most of the clausulae in Cicero (Cicero, Marcus Tullius)'s speeches, for example, follow a specific pattern and distinctly avoid certain types of rhythmic endings. The final words of a speech were an important element of its effectiveness. Thus, the quantity of syllables became the basis on which to establish a regular metrical sequence. Certain endings were regarded as strong and were preferred; others were avoided as weak.