Stillson wrench: Meaning and Definition of

Still'son wrench"

Pronunciation: (stil'sun), [key]
— Trademark. Trademark.
  1. a monkey wrench with a pivoted, adjustable jaw that grips pipes, bars, etc., more tightly when pressure is exerted on the handle.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.