fourfold purchase
noun
a tackle that is composed of a rope passed through two fourfold blocks in such a way as to provide mechanical power in the ratio of 1 to 5 or 1 to 4, depending on whether hauling is done on the running or the standing block and without considering friction.
Compare tackle(def 2).
Words nearby fourfold purchase
fourché,
fourdrinier,
fourflusher,
fourfold,
fourfold block,
fourfold purchase,
fourgon,
fourier,
fourier analysis,
fourier series,
fourier transform