erythroblastosis fetalis: severe anemia in newborn babies; the result of Rh incompatibility between maternal and fetal blood; typically occurs when the child of an Rh-negative mother inherits Rh-positive blood from the father; can be diagnosed before birth by amniocentesis
entity: that which is perceived or known or inferred to have its own distinct existence (living or nonliving)
chassis: the skeleton of a motor vehicle consisting of a steel frame supported on springs that holds the body and motor