[ad. L. ēruptiōn-em, n. of action f. ērumpĕre: see ERUMPENT. Cf. Fr. éruption.]
1. The bursting forth (of water, fire, air, etc.) from natural or artificial limits.
1555. Eden, Decades W. Ind., III. VIII. (Arb.), 173. Eruptions of the springes owte of the montaines.
1605. Verstegan, Dec. Intell., iv. (1628), 100. The great harmes that these parts haue heretofore by eruption of the sea sustained.
1669. Boyle, Contn. New Exp., II. (1682), 128. The compressed air suddenly finding out a way of eruption.
1725. De Foe, Voy. round World (1840), 243. I sat up almost all the night staring out from the window at the eruption of fire upon the hills.
1774. Pennant, Tour Scot. in 1772, 22. Pelling moss, which … made an eruption similar to that of Solway.
1819. G. S. Faber, Dispensations (1823), I. 106. During the whole sixteen centuries, which intervened between the sentence of Cain and the eruption of the deluge.
1830. Lyell, Princ. Geol., I. 287. One of the most memorable eruptions occurred in 1421, where the tide … burst through a dam … and overflowed twenty-two villages.
¶ Used for: The bursting (of a gun). rare–1.
1660. T. Willsford, Scales Commerce, 192. All guns … perpetrated with cold and frosty weather are most subject to an eruption at the first shot.
b. concr. That which bursts forth; a sudden rush of flame, smoke, water, etc.
1699. Garth, Dispens., 6. From the Vulcano’s gross eruptions rise.
1717. Berkeley, in Fraser, Life, 581. The streets of Naples … paved with the matter of eruptions.
1728. Mallet, Excursion, 42. With black Eruption in foul Storm A Night of Smoke … Rolls forth.
1774. Pennant, Tour Scotl. in 1772, 67. The eruption burst from the place of its discharge, like a cataract.
2. An outbreak of volcanic activity; the ejection of solid or liquid matter by a volcano, of hot water from a geyser, etc.
[1603. Holland, Plutarch’s Mor., 1190. The breakings forth and eruptions of fire out of a mountaine.]
1740. Gray, Lett., in Poems (1775), 94. A Roman town that was overwhelmed by a furious eruption of Mount Vesuvius.
1794. R. J. Sulivan, View Nat., II. 133. Iceland chronicles give a list of 63 eruptions at Heckla.
1857. Dufferin, Lett. High Lat. (1867), 87. Our principal object in coming … was to see an eruption of the Great Geysir.
1876. Page, Adv. Text-bk. Geol., iii. 50. Consolidated products of volcanic eruption.
3. Of persons: The action of breaking forth, of issuing suddenly and violently from within boundaries; e.g., the sallying forth of armed men from a stronghold, or of a horde of barbarians from their own country, the forcible escape of a prisoner, etc. rare in recent use.
1615. G. Sandys, Trav., 43. Two hundred and fourteene yeares after their eruption out of Scythia.
1623. Th. Ailesbury, Sermon (1624), 17. In that eruption of the Prodigall sonne from his Father.
1638. Heywood, Rape Lucr., Wks. 1874, V. 205. The enemie is pounded fast In their owne folds … There’s no eruption to be feared.
1652. Needham, trans. Selden’s Mare Cl., 262. Danegeld for the pay of those that should be imploied to hinder the eruption of Pirates.
a. 1677. Barrow, Pope’s Suprem. (1687), 181. The eruptions of Barbarians, the straits of Emperours … &c. did all turn to account for him.
1775. Johnson, Tax no Tyr., 18. Of this kind were the eruptions of those nations.
1822. Q. Rev., XXVII. 377. Securing to them the benefits of prison-discipline, by providing against furtive or forcible eruptions.
4. fig. In many obvious applications of the sense ‘outbreak’: An outbreak of disease, war, calamity, or evil of any kind; an outburst of passion, eloquence or merriment; a ‘sally’ of wit. Now rare, except with distinct allusion to sense 2.
1588. Shaks., L. L. L., V. i. 121. The Curate and your sweet self are good at such eruptions, and sodaine breaking out of myrth. Ibid. (1602), Ham., I. i. 69. This boades some strange erruption to our State.
1656. Owen, Mortific. Sin (1668), 47. A man may be sensible of a lust, set himself against the eruptions of it.
1680. Life Edw. II., in Select. fr. Harl. Misc. (1793), 34/2. The archbishop of York … resolves to oppose this over-daring and insolent eruption.
1762–71. H. Walpole, Vertue’s Anecd. Paint. (1786), V. 107. Before the eruption of the civil war.
a. 1847. Mrs. Sherwood, Lady of Manor, III. xviii. 32. There is nothing which retards the progress of the Gospel so much as the remaining eruptions of sin among the rulers of the Church.
1883. G. A. MacDonnell, Chess Life-Pictures, 8. The twirling of that ornament [a large eye-glass] in his hand, like the rolling to and fro of Doctor Johnson, ever portended an anecdotal or jocose eruption.
5. † a. In plants: The bursting forth from the bark of buds, leaves, offshoots, roots, etc.; also concr. an excrescence. Obs. b. Of the teeth: The action of breaking out from the gums, in the process of ‘cutting the teeth.’
a. 1626. Bacon, Sylva (1631), § 588. When they [the branches] make an Eruption, they breake forth casually, where they finde best way in the Barke or Rinde.
1660. Sharrock, Vegetables, 142. Both Buds and Leaves, and all eruptions, stand so on every Vegetable, as serve most fitly for most necessary ends.
1671. Grew, Anat. Plants, I. 27. The place of their [Trunk-Roots’] Eruption is sometimes all along the Trunk; as in Mint, &c.
1713. Derham, Phys.-Theol., X. i. 447, note. The Art in Folding up the Leaves before their eruption out of their Gems, &c. is incomparable.
b. 1859. J. Tomes, Dental Surg., 104. The relations of the eruption of the permanent teeth to the age of the individual.
1863. Huxley, Man’s Place Nat., II. 83. The order of eruption of the permanent teeth is different.
6. Path. a. A breaking out of a rash, or of pimples on the skin. (In early use with notion of a ‘breaking out’ of latent disease or of ‘peccant humours.’)
1596. Shaks., 1 Hen. IV., III. i. 27. Diseased Nature oftentimes breakes forth In strange eruptions.
1674. Govt. Tongue, vi. 102. When there is an eruption of Humor in any part, tis not cured meerly by outward applications.
1731. Arbuthnot, Aliments, 172. Some Sorts of cutaneous Eruptions are occasion’d by feeding much on acid unripe Fruits.
1799. Med. Jrnl., I. 322. An eruption of pimples on that day, which disappeared on the next.
b. The skin affection itself; an efflorescence, rash.
1770. Junius Lett., xxxix. 203. No man regards an eruption upon the surface, when he feels a mortification approaching to his heart.
1802. Med. Jrnl., VIII. 147. The matter … scarcely ever afforded any eruptions like the small-pox.
1846. J. Baxter, Libr. Pract. Agric. (ed. 4), II. 156. A scaly eruption appears, attended by extreme itching.
1882. Squire, in Quain Med. Dict., 927. The declining rash of measles leaves a mottling of the skin, not unlike the mulberry eruption of typhus.
Hence Eruptional [+ -AL], a., of or pertaining to volcanic eruption.
1858. G. P. Scrope, Geol. & Volcanoes Centr. Fr. (ed. 2), 212. It may have sustained considerable absolute elevation … during its eruptional era.
1883. Proctor, in Knowledge, 30 June, 384/2. When there are few spots or none on the sun’s surface, the eruptional or jet prominences are not seen.
