microsomia
/ˌmʌɪkrə(ʊ)ˈsəʊmɪə/Medicine
noun
1Abnormally small size of the body (dwarfism); (in full microsomia fetalis) abnormally small size of the fetus for gestational age. Compare macrosomia rare. Perhaps Obsolete.
2With distinguishing word: underdevelopment of part of the face, as a congenital malformation.
Origin
Mid 19th century. From Italian microsomia from micro- + ancient Greek σῶμα body + -ia.