Dictionary entry

Calipers

Webster's Dictionary 1913

Cal″i‐pers (?), n. pl. [Corrupted from caliber.] 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.

Caliper square, a draughtsman's or mechanic's square, having a graduated bar and adjustable jaw or jaws. Knight.Vernier calipers. See Vernier.