Confused, I looked for other uses of the term barrel knot and found this snippet on the Animated Knots page for a barrel hitch (emphasis mine):
"Barrel" Confusion: Unfortunately, the name Barrel has been applied to various other knots. Ashley himself used it as an alternative name (ABOK # 1413, p 259) for the Blood Knot. Some have applied it to the Poacher's Knot, e.g., descriptions by IRATA and Access Techniques, and others to the Double Fisherman's, e.g., Cave Now.
Barrel knot (blood knot) - joins sections of monofilament nylon line while maintaining much of the line's inherent strength
However, the blood knot and double fishermans/double overhand are definitely different knots.
So what's happening here? Is this just another name for the same knot, or is this a clear misuse of the name by a well-established climbing website?