The article presents and analyses the ethnomusicological terminology used by Professor Mykolas Biržiška (1882–1962), an outstanding scholar, publicist, and researcher of traditional Lithuanian songs. The scientific activity of M. Biržiška was very extensive. He researched old Lithuanian literature, wrote textbooks, and published many articles. They include ‘The Life and Writings of Donelaitis’, ‘Textbook of Lithuanian Song Literature’, ‘The History of Our Literature’, ‘Our Ancient Writings’, ‘Old Vilnius University’, ‘Lithuanian Geography’, and others. He was particularly interested in the history of traditional Lithuanian culture, and tried to systematise Lithuanian literature, provide a general overview of it, and systematise all collected Lithuanian folk songs. He drew attention to various important features of Lithuanian folk songs in his writings. An important part of this research was devoted to the analysis of the composition of Lithuanian folk songs and the development of a system for their classification. In Biržiška’s times the dictionary of Lithuanian ethnomusicological terminology had not yet been formed, so he had to create new terms and propose new concepts for these terms. His works on the creation of ethnomusicological terminology are also of interest to contemporary scholars: ethnomusicologists, folklorists, and researchers of traditional Lithuanian singing and instrumental folklore.