A song is voice music—unless it is Songs Without Words
A song is a musical composition for the human voice, usually carrying melody through patterns of sound and silence. Structure often repeats sections, as in ABA form; without instruments it is a cappella. Yet semantic widening lets nineteenth-century piano Songs Without Words borrow the name.
Words written for music are lyrics; a pre-existing poem set by a classical composer becomes an art song. Chants ride repeated pitches without rising and falling contours. Folk songs travel by ear in simple style; popular songs aim at mass markets and professional singers. Large classical vocal forms prefer aria and recitative over the word song. Accompaniment ranges from none to guitar, piano, jazz combo, big band, or orchestra. Jazz and blues singers may learn by ear and improvise; classical singers read scored melodies.
German Kunstlied marks serious art song against Volkslied; early Schubert Lieder can still be strophic while accompaniments grow sophisticated enough to carry melody against a dramatic vocal line. Troubadours, Elizabethan lutenists, and Henry Purcell seed the romance tradition that later enters nineteenth-century opera. Folk repertories include ballads, lullabies, work songs, and ritual pieces; popular shelves add torch songs, anthems, rock, blues, and soul. Sporting songs once celebrated hunts and races; D'ye ken John Peel entered The National Song Book in 1906 as a march.
Late Renaissance and early Baroque lute songs, mainly English and French, favoured strophic homophony for solo voice and lute, sometimes with bass viol. Part songs arrange secular polyphony for SATB or single-sex choirs. Patter songs fire syllables one-to-a-note at comic-opera speed, a Gilbert and Sullivan staple that crossed into musicals. Whether studio take or theatre cue, the voice-centered definition still organizes the map—even when Mendelssohn-style instrumentals steal the label.
Source: Song
