Scotch Snap – a rhythm consisting of a short note followed by a long one

(Pronounced scoch snap)

To remember what scotch snap means, use the following mnemonic:

He asked for more scotch and snapped (scotch snap) his fingers. He wanted a short glass followed by a long glass.

Often used in hip hop. 

The sound pattern can be found if you say Teenage Mutant Ninja Turtles to a drum beat i.e.

So it's a stressed syllable followed by a weak syllable.