adjective Cephalometry, Pathology.
having a head with a small braincase.
Also, microcephalous [mahy-kroh-sef-uh-luhs] .

1855–60; < Neo-Latin microcephalicus. See micro-, cephalic

microcephaly, noun
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World English Dictionary
microcephaly (ˌmaɪkrəʊˈsɛfəlɪ)
Compare megacephaly the condition of having an abnormally small head or cranial capacity
adj, —n

Collins English Dictionary - Complete & Unabridged 10th Edition
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Word Origin & History

1856, from Fr. microcéphalique, from Mod.L. microcephalus, from Gk. mikros "small" (see mica) + kephale "head."
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary

microcephaly mi·cro·ceph·a·ly (mī'krō-sěf'ə-lē)
Abnormal smallness of the head. Also called nanocephaly.

mi'cro·ce·phal'ic (-sə-fāl'ĭk) adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Encyclopedia Britannica


condition of abnormal smallness of the head. Microcephalic individuals are usually severely retarded both mentally and developmentally. Primary microcephaly results when the brain itself is abnormally small (microencephaly), so that there is no stimulus for the vault to grow. It also occurs when all the cranial sutures fuse prematurely, precluding brain growth. Irradiation of the abdomen in pregnant women or maternal (and via the placenta, fetal) infection with German measles or toxoplasmosis during the first three months of pregnancy may sometimes produce a microcephalic child. Microcephaly of greater or lesser degree also accompanies various genetic syndromes such as Hurler's syndrome and some chromosomal disorders.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Example sentences
When these genes malfunction, the result is a condition called primary microcephaly, in which brain size is severely diminished.
Consider microcephaly, an autosomal recessive disease.
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