Illustration from 1908 Chambers's Twentieth Century. <b>Sister-hook</b>, in a ship's rigging, one of a pair of hooks fitting closely together and working on the same axis—also <i>Clip-hook</i> and <i>Clove-hook</i>.
Rev. Thomas Davidson 1856-1923 (<i>ed.</i>)
Chambers's Twentieth Century Dictionary of the English Language