D defs.my
Entry 3 senses Webster, 1913

Effloresce

· Ef·flo·resce · IPA /ˌɛfləˈɹɛs/
01 v. i. To blossom forth.
imp. & p. p. Effloresced; p. pr. & vb. n. Efflorescing
  1. 1.
    To blossom forth.
  2. 2.
    To change on the surface, or throughout, to a whitish, mealy, or crystalline powder, from a gradual decomposition, esp. from the loss of water, on simple exposure to the air; as, Glauber's salts, and many others, effloresce.(Chem.)
  3. 3.
    To become covered with a whitish crust or light crystallization, from a slow chemical change between some of the ingredients of the matter covered and an acid proceeding commonly from an external source; as, the walls of limestone caverns sometimes effloresce with nitrate of calcium in consequence of the action of nitric acid formed in the atmosphere.