Definition of "thumbscrew" [thumb•screw]

• A screw designed so that it can be turned with the thumb and fingers. (noun)
• An instrument of torture formerly used to compress the thumb. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The thumbscrew was a little thing, but caused great agony."
• "About the definition of “torture”, I can see a need for scrutiny, since the real debate (pace His Andrewship) isn’t over whether the rack and the thumbscrew are acceptable methods of questioning but whether waterboarding, sleep deprivation and raucous music belong in the same odious category."
• "The first was a kind of thumbscrew; the second was a frame in which the leg was inserted, and in which it was broken by wedges driven in by a hammer; the third was also an iron frame for the leg, which was from time to time heated over a brazier."