ˈri:səs n. (in full rhesus monkey) a
small catarrhine monkey, Macaca mulatta,
common in N. India. ørhesus
baby an
infant with a haemolytic
disorder caused by
the incompatibility of
its own rhesus-positive
blood with its mother's rhesus-negative blood. rhesus
factor an
antigen occurring on the
red blood cells of
most humans
and some other primates (as in the rhesus monkey, in
which it
was first observed). rhesus
negative lacking the rhesus factor. rhesus
positive having the rhesus factor. [mod.L,
arbitrary use of L Rhesus f. Gk Rhesos, mythical
King of Thrace]