noun
: either of two knots used for tying fishing leaders together:
a. : a knot made by twisting the ends of two standing parts one around the other usually two or three times and then pushing the ends back through the center twist — called also blood knot
b. : a knot made by tying double or triple overhand knots with each end around the opposite standing part — called also double Englishman's knot, double fisherman's knot, grapevine knot