Pronunciation: (hip"u-bis'ul, hī"pu-), [key]
1. (of an igneous rock) intermediate in texture between coarse-grained intrusive rocks and fine-grained extrusive rocks.
2. noting any of various minor intrusions, as dikes and sills, that have crystallized under conditions intermediate between plutonic and extrusive.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.