What does rhesus mean?
Rhesus most commonly denotes the rhesus macaque, a widely distributed member of the macaque family that is native to South Asia and has been introduced into numerous other regions. The animals are adaptable, omnivorous, and often live near human settlements, where they may forage in cultivated areas. In medicine, rhesus also appears in terms such as rhesus factor and rhesus disease, referring to the Rhesus blood-group system. Its best-known clinical importance concerns Rh incompatibility, in which certain Rhesus antibodies can harm a fetus during pregnancy. The word has memorable origins: the animal takes its name from Rhesus, a legendary Thracian king of Greek mythology, while the blood-group terminology was named after experiments involving rhesus monkeys. Rhesus is therefore both a precise zoological designation and a familiar medical term connected with blood-group compatibility.
nounA macaque native to South Asia but introduced in many other regions, commonly known as the rhesus monkey. The name also refers to the Rhesus blood-group antigen system, particularly the factor responsible for Rh incompatibility.
- The rhesus macaque, a macaque native to South Asia and introduced elsewhere, also known as the rhesus monkey.
- The Rhesus blood-group antigen system, especially the factor associated with Rh incompatibility between a pregnant person and fetus.
"A troop of rhesus macaques forage among the trees near the village."
"A troop of rhesus macaques forage among the trees near the village."
"The report identifies the newborn as rhesus-positive."
The regular plural is rhesuses, although rhesus monkeys is more natural when referring collectively to the animals.
"Several rhesuses were photographed near the riverbank."
Your blood group has a monkey in its name: the Rh factor was named after rhesus monkeys.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does rhesus come from?
The word comes through Latin from Greek Rhêsos, the name of a legendary Thracian king associated with the Trojan War. The macaque's common name was taken from that mythological figure, and the name was later applied to the blood-group system because its key antigens were identified through work involving rhesus monkeys.
How rhesus is actually used
In the animal's common name, rhesus is normally lowercase. Medical writing variously uses Rh, rhesus, or Rhesus when discussing blood-group antigens, so capitalization may vary according to house style.