Dictionary.com
definitions

migmatite

noun
  1. a composite rock body containing two types of rock (esp igneous and metamorphic rock) that have interacted with each other but are nevertheless still distinguishable

Word Origin for migmatite

C20: alteration of Swedish migmatit, from Greek migma mixture + -ite 1
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
migmatite in Science

migmatite

[mĭg′mə-tīt′]
  1. A rock of both metamorphic and igneous origin, that exhibits characteristics of both rock types. Migmatites probably form through the heating (but not melting) of rocks in the presence of abundant fluids.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.