Concertina Wire - "Constantine" Wire

Concertina wire is sometimes mistakenly called "constantine" wire. "Constantine" probably came from a corruption/misunderstanding of "Concertina" and led to confusion with the Roman Emperor Constantine. This in turn has led to some people trying to differentiate between concertina wire and "constantine" wire by assigning the latter term to what is commonly known as razor wire. In contrast to the double-helical construction of concertina wire, as shown being deployed by soldiers in the image, razor wire, or less commonly "constantine wire", consists of a single wire with projecting teeth periodically along its length.