WordReference Random House Unabridged Dictionary of American English © 2026
Rh neg•a•tive
(är′āch′ neg′ə tiv).USA pronunciation
WordReference Random House Unabridged Dictionary of American English © 2026- PhysiologySee under Rh factor.
- 1955–60
Rh fac•tor,
(är′āch′ fak′tər),USA pronunciation [Physiol.]
- Physiologyany 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.
- so called because first found in the blood of rhesus monkeys 1940–45
'Rh negative' also found in these entries (note: many are not synonyms or translations):