calipers

noun

1. (plural, plural-only)A device used to measure dimensions, especially for small or precise measurements.

   “"Good, good for there," he mumbled, and then with a certain eagerness asked me whether I would let him measure my head. Rather surprised, I said Yes, when he produced a thing like calipers and got the dimensions back and front and every way, taking notes carefully.”

2. (UK, plural, plural-only)A metal (orthopedic) leg support.

   “And simultaneously I raise my trouser cuff to reveal the leather straps and wicked steel calipers harnessing my right boot.”