Period (music)

In music, form refers to the structure of a musical composition or performance. In his book, Worlds of Music, Jeff Todd Titon suggests that a number of organizational elements may determine the formal structure of a piece of music, such as "the arrangement of musical units of rhythm, melody, and/or harmony that show repetition or variation, the arrangement of the instruments (as in the order of solos in a jazz or bluegrass performance), or the way a symphonic piece is orchestrated", among other factors. It is, "the ways in which a composition is shaped to create a meaningful musical experience for the listener."

These organizational elements may be broken into smaller units called phrases, which express a musical idea but lack sufficient weight to stand alone. Musical form unfolds over time through the expansion and development of these ideas. In tonal harmony, form is articulated primarily through cadences, phrases, and periods. "Form refers to the larger shape of the composition. Form in music is the result of the interaction of the four structural elements," of sound, harmony, melody, and rhythm.

In music theory, a phrase (Greek: φράση) is a unit of musical meter that has a complete musical sense of its own, built from figures, motifs, and cells, and combining to form melodies, periods and larger sections.

Terms such as sentence and verse have been adopted into the vocabulary of music from linguistic syntax. Though the analogy between the musical and the linguistic phrase is often made, still the term "is one of the most ambiguous in music....there is no consistency in applying these terms nor can there be...only with melodies of a very simple type, especially those of some dances, can the terms be used with some consistency."

Musical phrasing is the method by which a musician shapes a sequence of notes in a passage of music to allow expression, much like when speaking English a phrase may be written identically but may be spoken differently, and is named for the interpretation of small units of time known as phrases (half of a period). A musician accomplishes this by interpreting the music—from memory or sheet music—by altering tone, tempo, dynamics, articulation, inflection, and other characteristics. Phrasing can emphasise a concept in the music or a message in the lyrics, or it can digress from the composer's intention, aspects of which are commonly indicated in musical notation called phrase marks or phrase markings. For example, accelerating the tempo or prolonging a note may add tension.

Giuseppe Cambini—a composer, violinist, and music teacher of the Classical period—had this to say about bowed string instruments, specifically violin, phrasing: