calipers(Noun)

A device used to measure thickness between two surfaces, especially for small or precise measurements.

Calipers(u)

an instrument, usually resembling a pair of dividers or compasses with curved legs, for measuring the diameter or thickness of bodies, as of work shaped in a lathe or planer, timber, masts, shot, etc.; or the bore of firearms, tubes, etc.; -- called also caliper compasses, or caliber compasses