caliper
Concise Oxford English Dictionary © 2008 Oxford University Press:
caliper /ˈkalɪpə/ (also calliper)
▶noun
- 1 an instrument for measuring external or internal dimensions, typically with two hinged legs and in-turned or out-turned points.
- 2 a motor-vehicle or bicycle brake consisting of two or more hinged components.
- 3 a metal support for a person's leg.
'caliper' also found in these Oxford entries:

