Complex sentence: In medicine, "heterotopia" refers to the displacement of an organ or part of an organ from its normal position, often specifically gray matter heterotopia, the displacement of gray matter into the cerebral white matter or ventricles.
Split into simpler sentences: In medicine, "heterotopia" refers to normal tissue present at an abnormal site or the displacement of an organ or part of an organ from its normal position. For example, gray matter heterotopia, the displacement of gray matter into the cerebral white matter or ventricles.