D defs.my
Entry 2 senses Webster, 1913

Thumbscrew

· Thumb·screw · IPA /ˈθʌmskɹuː/
01 n. A screw having a flat-sided or knurled head, so that it may be turned by the thumb and forefinger.
  1. 1.
    A screw having a flat-sided or knurled head, so that it may be turned by the thumb and forefinger.
  2. 2.
    An old instrument of torture for compressing the thumb by a screw; a thumbkin.