ballet:  Etymologically, a ballet is a ‘little dance’. English acquired the word, via French ballet, from Italian balletto, a diminutive of ballo ‘dance’, related to English ball (the diminutive of Italian balla ‘spherical ball’ is ballotta, whence English ballot). The noun ballo came from the verb ballare (a descendant via late Latin ballāre of Greek ballízein ‘dance’), of which another derivative was ballerino ‘dancing master’.
The feminine form, ballerina, entered English in the late 18th century. Balletomane ‘ballet enthusiast’ is a creation of the 1930s. Another word ballet, also a diminutive, exists, or at least existed, in English. It meant ‘little [spherical] ball’, and was used in the 18th century as a technical term in heraldry. => ball