Musicology (from Greek μουσική (mousikē), meaning "music", and -λογία (-logia), meaning "study of-") is the scholarly study of music. A person who studies music is a musicologist. The word is used in narrow, broad and intermediate senses. In the narrow sense, musicology is confined to the music history of Western culture. In the intermediate sense, it includes all relevant cultures and a range of musical forms, styles, genres and traditions, but tends to be confined to the humanities - a combination of historical musicology, ethnomusicology, and the humanities of systematic musicology (philosophy, theoretical sociology, aesthetics). In the broad sense, it includes all musically relevant disciplines (both humanities and sciences) and all manifestations of music in all cultures, so it also includes all of systematic musicology (including psychology, biology, and computing). The broad meaning corresponds most closely to the word's etymology, the entry on "musicology" in Grove's dictionary, the entry on "Musikwissenschaft" in Musik in Geschichte und Gegenwart, and the classic approach of Adler (1885).
In the broad definition, the parent disciplines of musicology include history; cultural studies and gender studies; philosophy, aesthetics and semiotics; ethnology and cultural anthropology; archeology and prehistory; psychology and sociology; physiology and neuroscience; acoustics and psychoacoustics; and computer/information sciences and mathematics. Musicology also has two central, practically oriented subdisciplines with no parent discipline: performance practice and research, and the theory, analysis and composition of music. The disciplinary neighbors of musicology address other forms of art, performance, ritual and communication, including the history and theory of the visual and plastic arts and of architecture; linguistics, literature and theater; religion and theology; and sport. Musical knowledge and know-how are applied in medicine, education and music therapy, which may be regarded as the parent disciplines of Applied Musicology.
Traditionally, historical musicology has been considered the largest and most important subdiscipline of musicology. Today, historical musicology is one of several large subdisciplines. Historical musicology, ethnomusicology, and systematic musicology are approximately equal in size - if numbers of active participants at international conferences is any guide. Systematic musicology includes music acoustics, the science and technology of acoustical musical instruments, physiology, psychology, sociology, philosophy and computing. Cognitive Musicology is the set of phenomena surrounding the computational modeling of music.