A binding knot can be used to grip and confine a single object. The most common example of a binding knot is the one you use to tie your shoes. Binding knots can also be used to combine and restrict a group of objects, like a bundle of firewood.
Knots used for binding should generally not be used for something else, such as a bend or hitch. Binding knots like the Reef or Square Knot need to stay flat against a surface, and they lose stability when subjected to the uneven forces that are at play with bends or hitches.
Making temporary repairs is one of the applications where binding knots really show their worth. Using knots that can hold tension on a binding can be especially useful. The tremendous grip of the Boa Constrictor Knot can be used to secure a wooden pole that has cracked. A regular Constrictor Knot works like a hose clamp and can be slipped for quick release.