·adj Causing a change of structure.
II. Metamorphic ·adj Subject to change; changeable; variable.
III. Metamorphic ·adj Pertaining to, produced by, or exhibiting, certain changes which minerals or rocks may have undergone since their original deposition;
— especially applied to the recrystallization which sedimentary rocks have undergone through the influence of heat and pressure, after which they are called metamorphic rocks.