A knot tied by making a full turn round something (typically the ring of an anchor), a half hitch through the turn, and a half hitch round the standing part of the rope.
Definition of fisherman's bend in US English:
fisherman's bend
noun
A knot tied by making a full turn around something (typically the ring of an anchor), a half hitch through the turn, and a half hitch around the standing part of the rope.