Meaning of laccolith

lac•co•lith

Pronunciation: (lak'u-lith), [key]
— n. Geol.
  1. a mass of igneous rock formed from magma that did not find its way to the surface but spread laterally into a lenticular body, forcing overlying strata to bulge upward.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.