Forms: 6 calleper, 7 calloper, -par, calloper, 7–8 callipper, 8 caliber, (canniper), 7– calliper, caliper. [App. the same word as CALIBRE; calliper compasses being compasses for measuring the calibre of a bullet, etc. The earliest known English instances of calliper compasses occur in a book translated from Italian, with an Appendix ‘to shew the Properties, Office, and Dutie of a Gunner.’ Cf. also Florio (1611) ‘Colibro, as Calibro, an instrument that Gunners vse to measure the height of any piece or bullet; also, the height or bore of any piece.’ It is however remarkable that from the beginning the words were spelt differently; only in modern times do we find occasional conscious identification with caliber, calibre.]
1. Originally used attrib., calliper compasses or compasses calliper, compasses used to measure the calibre of shot; afterwards usually in pl. callipers or pair of callipers: A kind of compasses with bowed legs for measuring the diameter of convex bodies; often with a scale attached for reading off the measurements; also a similar instrument with straight legs and points turned outwards for measuring the bore or internal diameter of tubes, etc.
1588. Lucar, trans. Tartaglia’s Colloq. Shooting, App. 35–6. Measure first with a paire of calleper compasses, or with an ynch rule the whole thickness of the peece. Likewise measure with a paire of other compasses, I mean straight compasses … the Diameter … of the concauitie in the Peece.
1627. Capt. Smith, Seaman’s Gram., xiv. 68. Compasse Callipers belongs to the Gunner, and is like two half Circles that hath a handle and ioint like a paire of Compasses.
1644. Nye, Gunnery, I. (1647), 49. To take the said height or Diam: of the shot with a pair of Callaper compasses. Ibid. (1670), 50. Also by such a pair of Callapers you may find the Diameter of the Base-Ring, and of the Mussel-Ring of any Piece of Ordnance.
1677. Moxon, Mech. Exerc. (1703), 196. Callippers measure … any round Cilindrick Conical Body.
1692. in Capt. Smith’s Seaman’s Gram., II. viii. 97. To find the Diameter of any round Shot … by a pair of Calloper Compasses, which are Compasses bowed at the Points.
1753. Hogarth, Anal. Beauty, Introd. 47. These points may be marked upon a marble figure with calibers properly used.
1795. Home, in Phil. Trans., LXXXVI. 6. Measured by a pair of calliper compasses.
1821. Craig, Lect. Drawing, vii. 372. An anvil, a hammer, and a pair of calipers.
1859. Smiles, Self-Help, 267. Moral philosophy which proposes to measure our heads with callipers.
1876. Catal. Sci. Appar. S. Kens., No. 284. Universal Calliper, with slide and reverse action. No. 271. Calliper with Dial … divided into eighths of an inch.
b. Applied to measuring rules of varying shape for taking the dimensions of other than round bodies. Calliper-square, a rule or square carrying movable cross-heads, adapted for the measurement of internal and external diameters or sizes.
1708. Kersey, Callipers, an instrument made like a Sliding-Rule, to embrace the two Heads of a Cask, or Barrel, in order to find the length of it.
1876. Catal. Sci. Appar. S. Kens., No. 293. Collection of Timber Callipers for the use of foresters.
Mod. techn. Calliper (in Liverpool timber yards), a rule for measuring timber, something like that which shoemakers use to measure feet.
2. transf. The clip for holding the load in a crane.
1769. De Foe’s Tour Gt. Brit., III. 272. Portable Cranes … to draw Stone out of the Quarry with Callipers.
3. Watch-making. ‘The disposition of the parts of a watch or clock; the arrangement of the train’ (Britten). App. akin to CALIBRE.
1884. F. J. Britten, Watch & Clockm., 151. As a matter of convenience in arranging the caliper of the watch.
