stillson wrench(n = noun.artifact) - a large pipe wrench with L-shaped adjustable jaws that tighten as pressure on the handle is increased;
is a kind of pipe wrench, tube wrench

   A pipe wrench having an adjustable L-shaped jaw piece sliding in a sleeve that is pivoted to, and loosely embraces, the handle. Pressure on the handle increases the grip. [Webster 1913 Suppl.]

adjustable wrench, allen wrench, alligator wrench, box end wrench, box wrench, brace wrench, bulldog wrench, carriage wrench, chain wrench, crescent wrench, dog wrench, hook wrench, lug wrench, monkey wrench, open-end wrench, pin wrench, pipe wrench, s wrench, screw wrench, socket wrench, sparkplug wrench, tap wrench, tappet wrench, torque wrench, tube wrench, wrench