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• rhesus
  rhesus

  noun

  a macaque, Macaca mulatta, of India, used in experimental medicine.
• Rhesus
  Rhesus

  noun

  Greek myth a king of Thrace, who arrived in the tenth year of the Trojan War to aid Troy. Odysseus and Diomedes stole his horses because an oracle had said that if these horses drank from the River Xanthus, Troy would not fall

rhesus

American  

[ree-suhs] / ˈri səs /

noun

1. a macaque, Macaca mulatta, of India, used in experimental medicine.

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Rhesus British  

/ ˈriːsəs /

noun

1. Greek myth a king of Thrace, who arrived in the tenth year of the Trojan War to aid Troy. Odysseus and Diomedes stole his horses because an oracle had said that if these horses drank from the River Xanthus, Troy would not fall

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Other Word Forms

• rhesian adjective

Etymology

Origin of rhesus

1830–40; < New Latin, arbitrary use of Latin Rhēsus name of a Thracian king allied with Troy < Greek Rhêsos

Example Sentences

In the study, pregnant rhesus monkeys were placed into different conditions.

From Science Daily • Feb. 6, 2026

On a tiny island called Cayo Santiago off the coast of Puerto Rico exists a colony of about 1,800 rhesus macaques.

From Salon • Mar. 16, 2025

The first macaque monkeys were cloned in 2018, but rhesus monkeys are preferred for medical researchers, because of their genetic similarity to humans.

From BBC • Jan. 16, 2024

They discovered that in failed rhesus attempts, the placentas, which provide oxygen and nutrients to the growing foetus, were not reprogrammed properly by the cloning process and so did not develop normally.

From BBC • Jan. 16, 2024

He drew off a little bit of fluid from the flasks and injected it into three rhesus monkeys, to infect them with the Cardinal agent.

From "The Hot Zone" by Richard Preston