Stretto (plural: stretti), from the Italian stringere "to draw close"'s a musical term for when a fugue motif's used to accompany itself. For example, if the alto voice begins the subject before the soprano voice has completed its prior entry of the subject, that's a stretto. A stretto's most often used to intensify the contrapuntal density of a piece, often signifying arrival at the fugue's conclusion, as seen in Johann Sebastian Bach's Well-Tempered Clavier Book I, Fugue No. 1 (External Shockw… (More on Stretto)