A song is a musical composition intended to be vocally performed by the human voice. This is often done at distinct and fixed pitches (melodies) using patterns of sound and silence. Songs contain various forms, such as those including the repetition and variation of sections.

Songs with more than one voice to a part singing in polyphony or harmony are considered choral works. Songs can be broadly divided into many different forms and types, depending on the criteria used. Through semantic widening, a broader sense of the word “song” may refer to instrumentals, such as Mendelssohn’s 19th century Songs Without Words pieces for solo piano.