Search Result for "thumbscrew": 
Wordnet 3.0

NOUN (2)

1. instrument of torture that crushes the thumb;

2. screw designed to be turned with the thumb and fingers; 



The Collaborative International Dictionary of English v.0.48:

Thumbscrew \Thumb"screw`\, n.
   1. A screw having a flat-sided or knurled head, so that it
      may be turned by the thumb and forefinger.
      [1913 Webster]

   2. An old instrument of torture for compressing the thumb by
      a screw; a thumbkin.
      [1913 Webster]


WordNet (r) 3.0 (2006):

thumbscrew
    n 1: instrument of torture that crushes the thumb
    2: screw designed to be turned with the thumb and fingers