von willebrand's disease: a form of hemophilia discovered by Erik von Willebrand; a genetic disorder that is inherited as an autosomal recessive trait; characterized by a deficiency of the coagulation factor and by mucosal bleeding
helmet orchid: any of numerous orchids of the genus Pterostylis having leaves in a basal rosette and green flowers often striped purple or brown or red with the dorsal sepal incurved to form a hood