ˈmäŋgəˌlizəm noun
or mon·go·li·an·ism mäŋˈgōlēəˌnizəm, mänˈ-, -lyəˌ-
( -s )
Usage: sometimes capitalized
Etymology: Mongol (II) or Mongolian (I) + -ism
: a congenital condition which is characterized by moderate to severe mental deficiency, by slanting eyes, by a broad short skull, by broad hands with short fingers, and by trisomy of the chromosome numbered 21 in man — called also Down's syndrome