Rh negative

Rh negative

[ahr-eych neg-uh-tiv]
noun
See under Rh factor.

Origin:
1955–60

Dictionary.com Unabridged

Rh factor

[ahr-eych fak-ter]
noun Physiology.
any of a type of specific antigen present on the surface of red blood cells, persons having inherited such antigens being designated Rh+ (Rh positive) and persons lacking them, a much smaller group, being designated Rh− (Rh negative) blood of Rh− persons is incompatible with Rh+ blood because of antibody reaction, and an Rh− woman who bears an Rh+ baby will have formed antibodies to the fetal blood that, unless removed from her bloodstream by apheresis in a subsequent pregnancy, will be carried across the placenta and destroy red blood cells of the next Rh+ fetus, resulting in erythroblastosis in the newborn.

Origin:
1940–45; so called because first found in the blood of rhesus monkeys

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Collins
World English Dictionary
Rh factor
 
n
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]

Rh negative
 
n
1.  blood that does not contain the Rh factor
2.  a person having such blood

Collins English Dictionary - Complete & Unabridged 10th Edition
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Etymonline
Word Origin & History

Rh factor
1942, from rh(esus) (q.v.); so called because the blood group, and its effects, were discovered in the blood of rhesus monkeys (1941).
Online Etymology Dictionary, © 2010 Douglas Harper
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American Heritage
Medical Dictionary

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.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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American Heritage
Science Dictionary
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.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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American Heritage
Cultural Dictionary
Rh factor [(ahr-aych)]

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.
The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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