▪ I. centring, centering, vbl. n.
(ˈsɛnt(ə)rɪŋ)
Also centreing.
[f. centre v. + -ing1; the standard spelling (on the analogy of settle, etc.) is now centring, but as the word is of 3 syllables (in careful pronunciation), centering (more rarely centreing) has freq. been used, esp. in technical senses.]
1. The action of the verb centre; placing in the centre, convergence to the centre.
| 1667 Milton P.L. ix. 109 As God in Heav'n Is Center, yet extends to all, so thou [Earth] Centring receav'st from all those Orbs. a 1732 Atterbury (J.) The visible centring of all the old prophecies in the person of Christ. |
2. A placing in the centre or making central; the bringing of two or more centres into coincidence; spec. the setting of lenses so that their axes are in the same straight line.
| 1768 E. Buys Dict. Terms of Art, Centering of an Optick-glass, is the grinding it so that the thickest part is exactly in the Middle. 1831 Brewster Optics xliii. 358 The..risk of imperfect centering, or of the axes of the three lenses not being in the same straight line. 1881 Edin. Rev. Oct. 537 Mr. Carter recommends that people should look to the centreing of their spectacles for themselves. 1883 Daily News 10 Sept. 2/1 When the ring rotates at high speed, any slight error of centring tends to injure the ring. |
3. Arch. ‘The temporary woodwork or framing, whereon any vaulted work is constructed’ (Gwilt).
| a 1766 Parentalia in Entick London (1766) IV. 206 Both centering and scaffolding. 1861 Smiles Engineers II. 182 The centering upon which the arches of the bridge were built. 1879 Sir G. Scott Lect. Archit. II. 194 The use of continuous timber centering. 1885 Ruskin Præterita iii, Well-made centreings..made this model..attractive. |
4. attrib. and Comb., as centring motion, centring punch (sense 2), centring stone (sense 3).
| 1855 I. Taylor Restor. Belief 138 A centering-stone of that structure which in the age of the Antonines had arched over the Roman world. 1883 Knowledge 27 Apr. i, Secondary stage with centering motion [in a microscope]. 1884 F. J. Britten Watch & Clockm. 148 Another spring..carrying a fine centreing punch. |
▪ II. ˈcentring, -ering, -reing, ppl. a.
[f. as prec. + -ing2.]
That centres. spec. of a diphthong (see quot. 1952). Cf. central a. 1 d.
| 1647 Crashaw Poems 157 All-circling point, all cent'ring sphere, The world's one, round, eternal year. 1917 H. E. Palmer First Course of Eng. Phonetics i. 23 English diphthongs (or double-vowels)..four (in view of the fact that the tongue passes from the sides to the centre of the triangle) may conveniently be termed the Centring Diphthongs. 1952 A. Cohen Phonemes of English iv. 91 ‘Centring diphthongs’ (i.e. those with [ə] as second element.) Ibid. 100 There are three of these ‘centring diphthongs’ to be considered in English, [iə, uə, ɛə]. 1964 R. H. Robins Gen. Linguistics iii. 98 These last three diphthongs are often called centring diphthongs, from the direction of their movement. |