glissando explained
A continuous slide between two pitches, covering all intermediate frequencies
In Depth
A true glissando is a smooth, continuous pitch change, as produced by a trombone slide, a finger sliding along a string, or a voice scooping between notes. On the piano, the effect is approximated by rapidly sweeping the finger across the keys, producing all the white or black notes in between. Harps and keyboard instruments produce discrete glissandos; unfretted strings, trombones, and voices produce true continuous glissandos. The effect can be dramatic, comic, sensuous, or terrifying depending on context.
The opening clarinet glissando of Gershwin's Rhapsody in Blue was a happy accident — the clarinettist improvised the upward slide during a rehearsal and Gershwin loved it.