-iks noun plural but usually singular in construction
Etymology: German agogik, from Greek agōgē + German -ik -ics
1. : the musical theory that rhetorical emphasis involves not only dynamic stress but also the emphasis implied in the greater relative length of the tones to be emphasized — compare rubato
2. : the quantitative aspect of musical nuances involving all variations from the rigid basic meter (as of retard, pause, accelerando)