Definition of riving knife in US English:

riving knife

noun

  • 1A knife for cleaving or splitting lengths of timber; a froe.

  • 2A safety device on a table saw which sits in the kerf close behind the teeth of the saw and moves along the workpiece with the saw, thereby preventing both the workpiece from being lifted by the emerging teeth and chips from being thrown up towards the operator.

Origin

Mid 19th century; earliest use found in Journal of the Franklin Institute.