megalencephaly
/ˌmɛɡəlɛnˈsɛfəli/ /ˌmɛɡəlɛnˈsɛf(ə)li/ /ˌmɛɡəlɛnˈkɛfəli/(also megaloencephaly) Medicine
noun
Enlargement of all or part of the brain (and usually the head), occurring as a benign inherited trait or as a manifestation of various metabolic or developmental abnormalities.
Origin
Early 20th century. From megalo- + -encephaly; apparently coined by F. W. Andrewes.