Also 5–6 comprysion, -prission. [a. F. compression, ad. L. compressiōn-em, n. of action, f. comprimĕre (ppl. stem compress-): see COMPRESS v.]
1. The action of compressing; pressing together, squeezing; forcing into a smaller compass; condensation by pressure.
c. 1400. Lanfranc’s Cirurg. (MS. A), 23. A gristil … haþ sixe helpingis [uses] … þo .ij. þat þe harde schulde not hirte þe neische, nameli in þe tyme of compressioun [v.r. comprission], & in þe tyme of smytinge.
1597. Lowe, Chirurg (1634), 58. Cast forth by the great dilation of the heart or else by the great comprysion thereof.
1599. Soliman & P., I., in Hazl., Dodsley, V. 289. Why, what is jewels, or what is gold, but earth; An humour knit together by compression.
1659. Leak, Water-wks., Pref. 3. Water cannot be forced by compression to be contained in less space then its Natural extension.
1774. Goldsm., Nat. Hist. (1776), II. 59. The infant itself has milk in its own breasts, which may be squeezed out by compression.
1863. Tyndall, Heat, i. § 7 (1870), 6. To consider the development of heat by compression.
b. Constraint, coercion.
1880. Ch. Times, 10 Nov., 779. Dwelling chiefly upon the causes of modern infidelity in France, [he] does not hesitate to ascribe it in a great measure to the compression exercised by Louis XIV.
c. fig. The condensation of thought or language.
1820. Miss Mitford, in L’Estrange, Life (1870), II. v. 92. Great as our merits might be in some points, we none of us excelled in compression.
1850. Mrs. Jameson, Leg. Monast. Ord., Pref. (1863), 15. The difficulty of compression has been the greatest of all my difficulties.
2. A state or condition of being compressed.
1603. Florio, Montaigne, I. xx. (1632), 43. Those instruments that serve to discharge the belly, have their proper compressions and dilatations, besides our intent, and against our meaning, as these are destined to discharge the kidneis.
1771. Mackenzie, Man of Feel. (1886), 37. His fingers lost their compression.
1849. Murchison, Siluria, ix. 204. Every variety of distortion and compression.
1871. Tyndall, Fragm. Sc. (ed. 6), I. ix. 300. The moraine is in a state of longitudinal compression.
b. of thought, language, or writing.
1759. Johnson, Idler, No. 70, ¶ 4. Best pleased with involution of argument, and compression of thought.
1823. J. Badcock, Dom. Amusem., p. vi. The state of compression in which it [the treatise] now appears.
c. fig. Straitened or repressed condition, under the operation of trouble, tyranny, or the like.
1762. Miller, trans. Duhamel’s Husb., II. ii. (ed. 2), 190. The state of compression which those in the common way were in after harvest.
1816. T. Jefferson, Writ. (1830), IV. 280. That nation is too high-minded … to remain quiet under its present compression.
1879. Farrar, St. Paul (1883), 523. That previous letter … had been written in much tribulation and compression of heart.
3. Compression of the poles: the flattening of a planet at the poles, making it an oblate spheroid.
1816. Playfair, Nat. Phil., II. 179. The compression of Jupiter amounts to a fourteenth part of his longer diameter.
1849. Mrs. Somerville, Connect. Phys. Sc., iv. 34. Of ascertaining the compression of Jupiter’s spheroid.
† 4. Surg. A compress. Obs. rare.
1599. A. M., trans. Gabelhouer’s Bk. Physicke, 110/1. We must also have for the same intente, Compressions, or little pillowes of inveterate linnen.
b. Short for ‘compression of the brain.’
1847. South, trans. Chelius’ Surg., I. 410. It is often very difficult to distinguish between drunkenness and either concussion or compression.
1870. T. Holmes, Surg. (ed. 2), II. 257. In well-marked compression, however, the patient is generally perfectly insensible.
5. attrib. and Comb., as compression bellows, chamber, machine, treatment; compression-casting, a method of casting bronzes, etc., in which the metal is forced by compression into the finer tracery of the mold; compression-cock, a tap having a collapsible india-rubber tube.
1852. Seidel, Organ, 26. Kaufmann, of Dresden … invented the so-called compression-bellows.
1874. Knight, Dict. Mech., I. 603/1. The compression-chamber receives its successive charges of air from the atmosphere by valves opening inward. Ibid. The power of such a compression machine.
