This thesis presents, through five long and independent essays, reflections about the theatricality (and performativity) of costume, considering it as a line of movement that is elaborated and materialized through objects positioned on the surface of the body of artists in scene. The theory about the costume, which is organized here, is a proposition that considers philosophy, historicity and artistic creation, and it tries to answer, once more, the insistent question "what is the costume design?", "what became the costume theatrical?" and "how the costumes movement can be observed at the scene and at the creative process?". To this, I elaborate a philosophy of costume pointing to a philosophical exercise and the conceptual dimension of this scenic element from an interlocution with the philosophies of fashion and the philosophical drafts about the costumes, adding definitions about the costume itself from the crisis of the term in the brazilian researches and also considering the costume theatricality through its relation with the time. Furthermore, I also present a historical trajectory of the relations of expansion of the objects of the costume, both from a didactical approach by proposing a diagram inspired by the Rosalind Krauss's diagrammatic framework for the expanded field, and also by talking about its efforts of movement at the time through the (de)composition of the imagetic standards through the gender disobedience and the relational propositions that dilute the boundaries between the self and the other. Integrating the perspective of the artistic creation, I present the experience of the production of costumes and the composition of the colors for the play "Figura Humana" ("Human Figure ") by Programa Tercer Abstracto (Brazil/Chile), starting from a critical analysis about the Oskar Schlemmer's artistic gesture and going beyond in the elaboration of costumes to expose the scenic composition through the variations of the body, the space, the time and the objects. This theory collaborates with the detachment of the costume from the obligations with the reproduction of the clothing habits, investing on its radicality through an observation of its material and discursive powers that are not reduced to the objects of the costumes, but that is inside its theatricality as a line of movement.