A miller's knot (also sack knot or bag knot) is a binding knot used to secure the opening of a sack or bag. Historically, large sacks often contained grains; thus the association of these knots with the miller's trade. Several knots are known interchangeably by these three names. Constrictor makes a fiercer binding knot, but Miller's/Bag is suitable for most applications, and is easier to tie/untie. Miller's/Bag makes a great hitch, like the similar Ground-Line. Binding usage has force emanating from inside rope ring evenly, hitch usage has force input from one side, then reducing around.