ef·fu·sive a.
  1. Pouring out; pouring forth freely. [archaic] “Washed with the effusive wave.”
  Effusive rocks Geol., volcanic rocks formed by a nonexplosive outpouring of lava in molten or plastic form; in distinction from so-called intrusive, or plutonic, rocks.
  -- Ef*fu*sive*ly, adv. -- Ef*fu*sive*ness, n.
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