|a children's mummer's parade, as on the Fourth of July, with prizes for the best costumes.|
|a screen or mat covered with a dark material for shielding a camera lens from excess light or glare.|
|Rh positive See also Rh negative Full name: rhesus factor an agglutinogen commonly found in human blood: it may cause a haemolytic reaction, esp during pregnancy or following transfusion of blood that does not contain this agglutinogen|
|[C20: named after the rhesus monkey, in which it was first discovered]|
|1.||blood containing the Rh factor|
|2.||a person having such blood|
Rh factor n.
Any of several substances on the surface of red blood cells that induce a strong antigenic response in individuals lacking the substance.
|Rh factor (är'āch') Pronunciation Key
Any of several antigens present on the surface of red blood cells in most humans. People with Rh factors are classified as having a blood type that is Rh positive, while people who lack the antigen are said to be Rh negative and can produce powerful antibodies that destroy red blood cells if given a blood transfusion from an Rh-positive donor. A woman who is Rh negative and is pregnant with an Rh-positive fetus can produce antibodies that are life threatening to the fetus. See Note at blood type.
Any of several substances found on the surface of red blood cells in persons.
Note: An Rh-negative woman who gives birth to an Rh-positive baby may develop antibodies to the Rh factor during her first pregnancy. These antibodies may cause a disorder in Rh-positive babies conceived afterward that could result in the death of the infant if the condition is not recognized and treated.