thumbscrew
/ˈθʌmskruː/noun
1
- （一般作thumbscrews）an instrument of torture for crushing the thumbs（折磨大拇指的）拇指夹。
2
- a screw with a protruding winged or flattened head for turning with the thumb and forefinger指旋螺钉, 蝶形（或翼形）螺钉。