According to Wikipedia, a ball-jointed doll is “any doll that is articulated with ball and socket joints.”  However, contemporary usage of the term refers more specifically to Asian ball-jointed dolls. “These are cast in polyurethane resin, a hard, dense plastic, and the parts strung together with a thick elastic. They are predominantly produced in Japan, South Korea, and China. The BJD style has been described as both realistic and influenced by anime. They commonly range in size from about 60 centimetres (24 in) for the larger dolls, 40 cm (16 in) for the mini dolls, and all the way down to 10 cm (4 in) or so for the tiniest of the tiny BJDs. BJDs are made to be easy to customize, by painting, changing the eyes and wig, and so forth.”

Anne, a 60cm ball-jointed doll.

(C) Amalia Leigh Boris, 2010