[ad. late L. truncātiōn-em, n. of action f. L. truncāre to TRUNCATE; cf. OF. troncacion (1495 in Godef.).]
1. The action of truncating; cutting short; maiming, mutilation. Also fig.
1579. Fulke, Heskins’ Parl., 262. The alteration, falsification, and truncation of Tertullians wordes.
1611. Cotgr., Troncation, a truncation, trunking, mutilation, cutting off.
1637. Prynne, Huntley’s Breviate, 48. Decreeing judgment of death, or truncation of members.
a. 1682. Sir T. Browne, Tracts, xiii. (1684), 204. Singular inhumanities in Tortures … The living truncation of the Turks.
1779–81. Johnson, L. P., Cowley, Wks. II. 69. In the Davideis are some … verses left imperfect … in imitation of Virgil, whom he supposes not to have intended to complete them: that this opinion is erroneous, may be probably concluded, because this truncation is imitated by no subsequent Roman Poet [etc.].
1903. F. W. H. Myers, Human Personality, II. 301. If it [death] be … a sheer truncation of moral progress.
2. In scientific and technical use: The process of truncating, or condition of being truncated; diminution by or as by cutting off an end or point, so that the object terminates in a straight edge or plane surface instead; spec. in Cryst. replacement of an edge or solid angle by a plane face, esp. one equally inclined to the adjacent faces.
1796. Kirwan, Elem. Min. (ed. 2), II. 203. White Lead Ore … Occurs … crystalized in … prisms, or pyramids, with or without truncations.
1803. H. J. Brooke, Introd. Crystallogr., 86. The rhomboid being converted into a six-sided prism by the truncation of all its solid angles, or of its terminal solid angles and its lateral edges.
1853. Kane, Grinnell Exp., xlv. (1856), 416. The truncation of the muzzle … set their faces in almost perfect and human-like oval.
1861. W. Pole, in Macm. Mag., III. 184/2. The corresponding facet … formed by the truncation of the lower … pyramid, is called the collet.
1874. Lyell, Elem. Geol., xxviii. 495. Similar … catastrophes have caused the truncation … of some large cones in Java.
b. transf. The place or part where something is truncated.
1805–17. R. Jameson, Char. Min. (ed. 3), 117. When we observe on a fundamental figure, in place of an edge or angle, a small plane, such a plane is denominated a Truncation.
1853. Phillips, Rivers Yorksh., iv. 135. The ‘High Peak’ … is at the truncation of an interior range of hills.
1897. Hazlitt, Suppl. Coinage European Cont., 29. This Portuguese piece has under the truncation of the bust the name of W. Wyon as the engraver.
