n. 翼形螺钉, 拇指夹

[机] 翼形螺钉, 蝶形螺钉

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.

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