This paper presents the Peircean Semiotics theory as a framework for music information domain representation, emphasizing the interpretant levels, which for Peirce (CP 5.475, CP 5.476) are: emotional (feelings and emotions), energetic (particular experiences) and logical (convention). This paper is part of a wider study on knowledge organization for music information that has been developed along two main lines: one on theoretical semiotics, and the other on applied semiotics. Barros, Café & Laplante (2016) presented some of the results of the applied study that involved interviews with young adults. We are now presenting results of the theoretical study based on Peirce’s works and his commentators. As main results, we propose four theoretical contributions to music information KO, distributed over two main lines, as follows: (1) The general constitution of music domain from a KO perspective: 1.1) The levels of meaning and the use of music information are parameters that need to be observed when mapping the field of music. 1.2) Concepts in the field of music should be analysed from the perspective of the semiosis process, as it is not possible to operate with isolated elements. (2) The nature of emotional concept construction: 2.1) Emotional concepts in the field of music do not follow linguistic conventions. 2.2) The function of objects in forming emotional concepts is not to adjust meaning to reality. We conclude It is now more essential than ever to return to concepts constructed from an unconventional perspective in order to analyse music knowledge organization.