[ad. L. efflōrescĕre, f. ex out + flōrescĕre to blossom, f. flōs, flōr-is a flower.]
1. † a. To bloom, burst forth into flowers (obs.). b. To burst forth into something resembling a flower. c. To burst forth as a plant when flowering; const. into.
1775. Sir E. Barry, Observ. Wines, 25. They will … begin to effloresce and shoot out into Flowers.
1807. Vancouver, Agric. Devon (1813), 432. Fungi germinate, effloresce, disseminate, and die, during the evolutions of the seasons.
1826. Good, Bk. Nat. (1834), II. 18. Zoophytes, or Plant-animals, so denominated from their efflorescing like plants.
1870. Rolleston, Anim. Life, 144. Efflorescing into two or three coecal ampullæ.
2. Chem. a. Of a crystalline substance: To change over the surface, or throughout, to ‘flowers’ or fine powder, owing to the loss of the water of crystallization on exposure to the air.
1788. W. Nicholson, trans. Fourcroy’s Nat. Hist. & Chem., II. 305. Some salts … readily effloresce, and continue to fall in pieces, till the whole becomes a fine white powder.
1791. Hamilton, trans. Berthollet’s Dyeing, I. I. III. i. 214. It effloresces, that is, it parts with its water of crystallization in the air, and assumes the appearance of flour.
1860. H. W. Reveley, in Jrnl. Soc. Arts, VIII. 323/2. Tufo, a volcanic production, never effloresces.
b. Of a salt: To come (in solution) to the surface (of the ground, etc.) and there crystallize. Also, To form a crust (by capillary attraction and evaporation) on the sides of a vessel containing a solution.
1820. T. Cromwell, Excurs. Ireland, vii. 61. The vitriolic particles … are seen to effloresce in various places.
1868. Dana, Min. (1880), 636. Mirabilite … effloresces with other salts on the limestone below the Genesee Falls.
c. Of the ground, a wall, etc.: To become covered with a powdery crust of saline particles left by evaporation from a solution that has been drawn to the surface by capillary attraction.
18[?]. Dana (W.). The walls of limestone caverns sometimes effloresce with nitrate of lime.
3. fig. a. (after 1) To ‘blossom out,’ break out into brilliant display. b. (after 2 c) Of hidden agencies, etc.: To come to the surface, become manifest.
1834. Foster, Ess. Evils Pop. Ignorance, 114. Knowledge … has seemed at last beginning to effloresce through the surface of the ground.
1837. Carlyle, Fr. Rev. (1872), III. III. i. 101. The secret courses of civic business … effervescing & efflorescing … as a concrete Phenomenon.
1864. Sat. Rev., 31 Dec., 812/1. A disposition … to effloresce into extremely tall talk.
1865. Pall Mall Gaz., 13 April, 10/1. The man who effloresces in later life into the full-blown social science orator.
