Plutarchus

Latin

From Koine Greek Πλούτᾰρχος (Ploútarkhos, from Ancient Greek πλοῦτος (ploûtos, “riches; Pluto”) +‎ ἀρχός (arkhós, “ruler”)).

Plūtarchus m sg (genitive Plūtarchī); second declension

Plutarch of Chaeronea (Lūcius Mestrius Plūtarchus, ca. 46 C.E. – 120 C.E.), a celebrated Graeco-Roman philosopher, historian, biographer, essayist, and priest at the Temple of Apollo in Delphi; best known for writing his Lives of the Noble Greeks and Romans, a biographical series commonly referred to as Plutarch's Parallel Lives.
a male given name from Ancient Greek, equivalent to Greek Πλούταρχος (Ploútarchos) or English Plutarch

Second-declension noun, singular only.