Megacephaly

Part of speech: noun

Definitions

1. An unusually enlarged head, often associated with a medical condition that causes the skull and brain to grow abnormally large
2. A condition in which a person's head is far larger than average, sometimes resulting from excess fluid or inherited developmental disorders
3. The state of having an oversized cranium, a trait that may be present from birth or develop due to an underlying disorder

Etymology: Megacephaly is built from two Greek elements. "Mega" comes from the Greek "megas," meaning great or large, and "-cephaly" comes from "kephalē," meaning head, so the word literally describes a great head. The combining form "-cephaly" appears in many medical terms, such as "microcephaly" for an unusually small head, and the two words are opposites built on the same root. The "mega-" prefix is the more familiar of the two, having reached modern English in words like "megaphone" and "megaton." Pairing it with "-cephaly" follows the pattern of medical and scientific vocabulary, where classical Greek elements are combined to name a physical condition precisely. The word was therefore coined from these classical parts rather than used by the ancient Greeks themselves.