ABSTRACT OBLIGATO / OBLIGÉ: A MUSICAL ETYMOLOGY Suzanne Anita Bratt Emily I. Dolan Ask for a definition of the musical term “obligato”; receive a different answer from everyone asked. What truth this axiom possesses lies in the multiple meanings acquired by the word during the past four hundred years. The varied definitions that presently circulate – an obligatory musical line, a virtuosic one, a filigree or descant, the use of a specific instrument, the use of organ pedal, the interaction of solo instrument and voice – all convey this complex legacy. Through analyses of music in manuscript, printed scores, and publishing materials, this dissertation concludes that certain meanings of “obligato” are active at different points in the history of Western musicking. Meanings activated by different instruments and in different genres can indicate the places of those instruments within an expected hierarchy, and can create those genres. This dissertation begins by considering certain in consistencies in the use of obligato terminology: situating scholarly discussion of the power of the obbligato violin in “Erbarme dich” alongside Sebastian Bach’s own use of the term. Similarly, Guido Adler’s construction of obligate Akkompagnement as a fundamental compositional principle for the Wiener klassische Schule is analyzed alongside his source for the term: a letter of Beethoven, written to a publisher, planning the appearance of the Septet op. 20. The overview undertaken in this section, of the complex publication history of the Septet, leads to a consideration of changing practices and expectations concerning music in print and manuscript. An analysis of obligato terminology at work in Breitkopf music catalogues locates one source of obligato’s multiple meanings: in the collision of the trio and accompanied sonata genres. Aspects of a voice and an instrument interacting often surface in connection with “obbligato.” This dissertation’s conclusion takes a wide-ranging approach to this phenomenon: analyzing musicologists’s conceptualizing the heard experience of certain arias, musical expectations and structures as embedded in concert practices, and discourses of the supernatural. Thus, a final point of consideration is Rousseau’s récitatif obligé: focusing not as much on the people playing the instruments, as on the instruments themselves replying to – and leading – those who sing.