- Italian: controsoggetto
In music, a countersubject is a melodic or thematic idea which is played against a primary subject of a fugue, ricercar, invention, sinfonia, or other contrapuntal piece of music. Generally a countersubject contrasts in character to a principal subject, so if the primary subject is a stately one in long note values, the countersubject is likely to be rhythmically more active, and vice-versa.
In a work which is not formally contrapuntal, i.e. not a fugue or an invention, a secondary theme playing against a primary theme is usually termed a countermelody.
countersubject in German: Kontrasubjekt
countersubject in French: Contre-sujet