A "thumbscrew" is a small metal device with two flat ends that you twist using your thumb and fingers. It was used in the past as a form of torture or punishment to apply pressure on someone's thumb or another body part. Full definition
Rather than thumbscrews on the back, small latches at the front allow the doors to swing open. (digitaltrends.com)
Gaines and Winchell lead Odessa Permian's powerhouse West Texas high school football team, annually putting themselves through the unimaginable crucible of small - town scrutiny and brutal conflict to allow the economically depressed, chemically dependent residents of Odessa a moment's respite from the banal thumbscrews of their everyday. (filmfreakcentral.net)
The interior offers easy access to components, thumbscrew side and PCI slot covers, and dual 120 mm fans for superior airflow. (velocitymicro.com)