Coˊchlea [in Mechanicks]

a screw, one of the six mechanick powers; it is a strait cylinder furrowed spiral-wise; if the furrowed surface be convex, the screw is said to be male: if concave, it is called a female screw. Where motion is to be generated, the male and female screw are always joined; that is, whenever the screw is to be used as a simple engine or mechanical power, when joined with an axis in Peritrochio, there is no occasion for a female; but in that case it beomes part of a compound engine.