A knot used to quickly and easily constrict, while still being easy to untie. If you needed it to be more secure, a half hitch would probably suffice.
Tie by making a lark's head, wrapping the two ends around your package, then feeding them in through opposite sides. Tighten up the lark's head and pull on the ends to tighten.
I'd prefer a trucker's hitch for long term: this is quick-n-dirty.
Probably has an ABOK number but I haven't looked.