Rhesus system

proper noun

A blood group system, the second most important after the ABO system, and important in human blood transfusion, whereby blood types are classified according to the presence ("positive") or absence ("negative") of potentially over 50 antigens, of which the most commonly referenced is RhD.

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Meanings

proper noun
  1. medicineA blood group system, the second most important after the ABO system, and important in human blood transfusion, whereby blood types are classified according to the presence ("positive") or absence ("negative") of potentially over 50 antigens, of which the most commonly referenced is RhD.

Origin

So named because the first identified antigen (RhD) was originally believed to be the same as one discovered in rhesus macaques.

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Cite this entry
APA

Rhesus system. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/Rhesus%20system

MLA

“Rhesus system.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/Rhesus%20system. Accessed November 3, 2026.

Chicago

WatkinsX Dictionary, s.v. “Rhesus system,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/Rhesus%20system.

Source: Rhesus system on Wiktionary, CC BY-SA 4.0.