Coenus or Koinos may refer to:
Coenus or Koinos (Greek: Κοῖνος), after Karanus, was the second king of the ancient kingdom of Macedon.
The Macedonian historian Marsyas of Pella relates the following aetiological story regarding his name: a certain Knopis from Colchis came to Macedonia and lived in the court of Caranus; when the royal male child was born, Caranus had the desire to name him after his father, Kiraron or Kararon, but the mother opposed and wanted after her father the child to be named. When Knopis was asked responded: by neither name. Therefore he was called Koinos (common).
Coenus (in Greek Koινoς; died 326 BC), a son of Polemocrates and son-in-law of Parmenion, was one of the ablest and most faithful generals of Alexander the Great in his eastern expedition. In the autumn of 334 BC, when Alexander was in Caria, and sent those of his soldiers who had been recently married, to Macedonia, to spend the ensuing winter with their wives there, Coenus was one of the commanders who led them back to Europe. In the spring of the year following (333 BC), Coenus returned with the Macedonians, and joined Alexander at Gordium. He commanded a portion of Alexander's army, and distinguished himself on various occasions. In all of Alexander's major battles, Coenus commanded the right-most battalion of infantry in the massive Macedonian phalanx. In the Macedonian battle tradition, the farther right you were in formation, the more honorable of a position you held. His distinction as commander of the "best" infantry of the phalanx indicates he was tactically reliable, probably extremely intelligent in warfare, and brave in battle; he was probably the epitome of the highly respected "lead-by-example" Macedonian general.
When Alexander had arrived at the river Hyphasis, and was anxious to push his conquests still further, Coenus was the first who had the boldness to urge the necessity of returning, and the king was obliged to follow his advice. But a short time afterwards, when the Macedonian army had actually commenced its return, Coenus died of an illness (326 BC), and was honoured by the king with a splendid burial. Alexander lamented his death, but is reported to have said, that Coenus had urged the necessity of returning so strongly, as if he alone had been destined to see his native country again.