A rhythmic figure characterised by a dotted note preceded by one of a shorter value; most often the precise figuration is semiquaver-dotted quaver. Often found in Scottish songs and dances, especially the Strathspey, which is partly distinguished by its use of this figure. The Scotch snap is a favourite device of those rather impressionable composers endeavouring to write Scottish-sounding music, but used wisely it can give great momentum to a melody.
The Scotch snap, or Scotch catch, is also known in a different context as a lombardic rhythm, as it was also found in the works of composers around the area of Lombardy in northern Italy. (The Oxford Dictionary of Music drily remarks that such composers "have never been within hailing distance of Scotland".)