metamorphic rock - Rock formed from igneous or sedimentary rock which has been geologically changed in its crystalline structure by great heat and pressure.
(metamorphic rock - Rock; formed; from igneous or sedimentary rock) (igneous or sedimentary rock; has been geologically changed; L:in its crystalline structure; by great heat and pressure)
metamorphic rock - Rock igneous or sedimentary rock
formed has been geologically changed
from igneous or sedimentary rock
L:in its crystalline structure by great heat and pressure