In order to describe the nature of opera as a polysemiotic artifact and to address the challenges around its transfer, reference is often made to the concept of "context," which, however, is usually used rather casually and intuitively and is rarely defined precisely. Building on the theory of synsemioticity, a somewhat tighter analytical grid will be presented that allows the extension of context to become clearer. This is achieved in two ways: first, the status of nonverbal in the polysemiotic artifact is addressed, which, referring to Catford, must be defined as co-text rather than as context. Second, it will be shown on which semiotic levels contextuality can be described. The examples given here are taken from the opera Orfeo ed Euridice (1762) by Christoph Willibald Gluck and from some of the translations in German and French based on this work. Pour decrire la nature de l'opera comme objet poly-semiotique et aussi saisir les defis poses par son transfert, on refere souvent au concept de 'contexte,' qui est cependant souvent utilise plutot superficiellement, intuitivement et rarement defini avec precision. En s'appuyant sur la theorie de la synsemioticite, on va presenter une grille d'analyse en quelque sorte plus rigoureuse, permettant d'etendre la notion de contexte qui devient ainsi plus claire. On y parvient de deux facons : d'abord en soulevant le statut du non-verbal dans l'objet poly-semiotique, defini, en renvoyant a Catford, comme cotexte plutot que comme contexte. Puis, on demontrera a quels niveaux semiotiques la contextualite peut etre apprehendee. Les exemples utilises sont pris de l'opera Orfeo ed Euridice (1762) de Christoph Willibald Gluck et de quelques-unes de ses traductions en allemand et en francais.