period.

About period

In music theory, the term period refers to forms of repetition and contrast between adjacent small-scale formal structures such as phrases. In twentieth-century music scholarship, the term is usually used similarly to the definition in the Oxford Companion to Music: "a period consists of two phrases, antecedent and consequent, each of which begins with the same basic motif." Earlier and later usages vary somewhat, but usually refer to notions of symmetry, difference, and an open section followed by a closure. The concept of a musical period originates in comparisons between music structure and rhetoric at least as early as the 16th century.