The first time that I heard the word “tourniquet” was in relation to first aid. It was a device that applied pressure by constriction to a person’s limb to stop excessive blood flow. It consisted of cordage or a strap that surrounded the limb in a loop slightly larger in circumference with enough slack to allow a stick to be inserted and twisted to enable the loop to begin the constriction process.
This constriction process has other applications as well. A tubeless tire that has lost air will typically withdraw from the wheel rims thus losing the seal and preventing inflation. By placing cordage around the circumference of the tire and affixing a cross piece, the tourniquet can be tightened around the tire causing the sidewalls to expand outward to contact the wheel rim thus enabling the tire to be inflated.
Another application can be used to tighten a chain link fence during installation. When a hand operated winch is not available, a chain can be used as a tourniquet that surrounds the fence post and stretcher bar. A crowbar is used as a cross piece for winding that will tighten the fencing into position for installation.
These are a few examples of tourniquet applications. I would be interested in learning of other applications in the comments below.