103. Continuo: a technique for providing a harmonic basis in the new homophonic music of the Baroque period. It was a style of accompaniment for a singer or one or two solo instruments. The bass line provided the underlying structure for the harmonies, and it usually was played on a cello. The chords were not completely notated and were improvised on a keyboard instrument, usually a harpsichord. The performer determined what chords to play from the bass line and the figured bass. The figures were numbers below certain notes of the bass line that served as a musical shorthand to indicate the harmonies.
104. Concerto: a three-movement work for solo instrument and orchestra that emerged during the Baroque period and has been a common instrumental genre ever since. The concerto grosso was an important genre of this period that featured a small group of soloists with orchestra. The arrangement of the movements is fast-slow-fast. Many concertos since the Baroque period include a cadenza, an unaccompanied passage in free rhythm in which the soloist displays his or her greatest virtuosity.
105. Sonata form: a structure that composers from the Classic period and since have commonly used for the first movement of a sonata, symphony, concerto, or string quartet (or other similar chamber music work). It includes three main sections: the exposition, development, and recapitulation and often begins with an introduction and ends with a coda. The exposition has two theme areas in contrasting keys. The development is based on material from the exposition. The recapitulation is a return to previous material stated in the exposition.
106. Fugue: an imitative polyphonic composition that originated as a keyboard genre during the Baroque period. It is, however, a compositional technique used during and since the Baroque in both choral and instrumental music. A fugue is built on a single theme whose entrances appear imitatively in several voices (melodic lines at different pitch levels), usually three or four, and then developed in intricate contrapuntal interplay.
107. Chorale: originally a hymn tune of the German Lutheran church sung by the congregation in unison and in the German rather than Latin language. It was an ougrowth of the Reformation and the rise of the Protestant church. Chorale tunes, especially during the Baroque era, were used as the bases for other compositions: they were harmonized in four-part settings for singing by choirs and congregations; they were used as the bases of sacred polyphonic compositions for trained choirs; and they formed the bases of organ pieces known as chorale preludes.
108. Cantata: an extended solo or choral work that flourished during the Baroque period. It was intended for the German Lutheran worship service, although some cantatas have secular texts. Choral cantatas, particularly those by J. S. Bach, include harmonized chorales, polyphonic choruses, arias, recitatives, solo ensembles, and instrumental accompaniment.
109. Oratorio: an extended sacred choral work intended for concert performance. It emerged during the Baroque period and has been a common genre since. It is of large proportions, lengthy (many lasting up to three hours), and dramatic in nature, sometimes including the character of a narrator as a soloist. Polyphonic choruses, arias, recitatives, solo ensembles, and orchestral accompaniment are common components of oratorios.
110. Aria: a lyrical song found in operas, cantatas, and oratorios. It may comment on the text presented in a recitative that preceded the aria.
111. Recitative: a vocal solo in opera, cantatas, and oratorios that declaims the text in a sung-speech manner, in free rhythm with minimal accompaniment, so that all listeners can understand the words. It frequently introduces an aria.