ˈwilyəmz- noun
Usage: usually capitalized W
Etymology: after J.C.P. Williams b 1922 New Zealand physician
: a rare genetic disorder characterized especially by hypercalcemia of infants, heart defects, characteristic facial features (as an upturned nose, long philtrum, wide mouth, full lips, and pointed chin), a sociable personality, and a high verbal aptitude, but with mild to moderate mental retardation