The boa knot is a modern, binding knot invented by weaver

Weaving

Weaving is a method of fabric production in which two distinct sets of yarns or threads are interlaced at right angles to form a fabric or cloth. The other methods are knitting, lace making and felting. The longitudinal threads are called the warp and the lateral threads are the weft or filling...

 Peter Collingwood in 1996. His intention was to develop a knot

Knot

A knot is a method of fastening or securing linear material such as rope by tying or interweaving. It may consist of a length of one or several segments of rope, string, webbing, twine, strap, or even chain interwoven such that the line can bind to itself or to some other object—the "load"...

 that would hold well when the constricted object was cut close to the winds of the knot.

The boa knot is related to the strangle knot

Strangle knot

The strangle knot is a simple binding knot. Similar to the constrictor knot, it also features an overhand knot under a riding turn. The difference is that the ends emerge at the outside edges, rather than between the turns as for a constrictor. This knot is actually a rearranged double overhand...

 and the double constrictor knot. It combines both the structure and qualities of these other two knots.

The boa knot is best used for securing objects in cylindrical loads.