What does microcephaly mean?
Microcephaly is a medical term for an abnormally small head, most often referring to a congenital condition in which the brain is also underdeveloped. It may be identified during pregnancy through ultrasound or after birth through measurement of head circumference, and it can be associated with developmental, neurological, or genetic difficulties. The severity and implications vary considerably, so the term describes a condition rather than a single uniform outcome. In everyday use, “microcephaly” is mainly encountered in medical and public-health contexts, including genetic counseling, prenatal screening, and pediatric diagnosis. The word comes from Greek roots meaning “small” and “head.” It is related to contrasting terms such as macrocephaly, which describes an abnormally large head, and to other medical terms ending in “-cephaly” that refer to the shape or size of the head.
nounA congenital condition in which the head is abnormally small, often accompanied by an underdeveloped brain. The term is also used more broadly for abnormally small head size, including some acquired forms.
- The congenital condition of having an abnormally small head, frequently associated with an underdeveloped brain.
- The condition or state of having a head circumference significantly smaller than expected for age and sex.
"Prenatal screening may identify fetal microcephaly, which requires careful medical evaluation."
"The child was evaluated for developmental concerns and was subsequently diagnosed with microcephaly."
"The report noted fetal microcephaly and recommended additional prenatal assessment."
Rarely pluralized; the word is ordinarily used as a mass noun referring to the condition.
"The study compared cases of microcephaly across several populations."
Microcephaly literally means “small head,” a name that captures its defining feature while leaving room for the many different conditions that can accompany it.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does microcephaly come from?
The word is built from the Greek mikros, meaning “small,” and kephalē, meaning “head,” with the combining form micro- also widely used in scientific vocabulary. Its medical sense developed alongside related terms such as macrocephaly, acrocephaly, and brachycephaly. The adjective forms microcephalic and microcephalous use the same Greek elements and describe a person or condition affected by an abnormally small head.
Related word forms
How microcephaly is actually used
This is primarily a medical term. It is used in diagnosis, genetics, pediatrics, and public-health reporting, and should be distinguished from the broad expression “small head” when describing a specific clinical condition.
Easily confused with microcephaly
Microcephaly means an abnormally small head, whereas acephaly describes the absence of a major portion of the brain and skull.