"The Oxford Companion to Music describes three interrelated uses of the term 'music theory.'"
The study of the principles, techniques, and theories that underlie music. It includes topics such as harmony, melody, rhythm, and texture.
"The first is the 'rudiments', that are needed to understand music notation; the second is learning scholars' views on music from antiquity to the present; the third is a sub-topic of musicology that 'seeks to define processes and general principles in music'."
"The musicological approach to theory differs from music analysis 'in that it takes as its starting-point not the individual work or performance but the fundamental materials from which it is built.'"
"Music theory is frequently concerned with describing how musicians and composers make music, including tuning systems and composition methods among other topics."
"A more inclusive definition could be the consideration of any sonic phenomena, including silence."
"The study of 'music' in the Quadrivium liberal arts university curriculum... was an abstract system of proportions."
"Music theory as a practical discipline encompasses the methods and concepts that composers and other musicians use in creating and performing music."
"The development, preservation, and transmission of music theory in this sense may be found in oral and written music-making traditions, musical instruments, and other artifacts."
"Ancient instruments from prehistoric sites around the world reveal details about the music they produced and potentially something of the musical theory that might have been used by their makers."
"Practical and scholarly traditions overlap, as many practical treatises about music place themselves within a tradition of other treatises, which are cited regularly just as scholarly writing cites earlier research."
"Etymologically, music theory is an act of contemplation of music, from the Greek word θεωρία, meaning a looking at, a viewing; a contemplation, speculation, theory; a sight, a spectacle."
"Music theory, as such, is often concerned with abstract musical aspects such as tuning and tonal systems, scales, consonance and dissonance, and rhythmic relationships."
"There is also a body of theory concerning practical aspects, such as the creation or the performance of music, orchestration, ornamentation, improvisation, and electronic sound production."
"University study, typically to the MA or PhD level, is required to teach as a tenure-track music theorist in a US or Canadian university."
"Methods of analysis include mathematics, graphic analysis, and especially analysis enabled by western music notation."
"Comparative, descriptive, statistical, and other methods are also used."
"Music theory textbooks... often include elements of musical acoustics, considerations of musical notation, and techniques of tonal composition (harmony and counterpoint), among other topics."