Home › Words › T › treerunnertreerunnertreerunner · noun — A bird of the genera Margarornis or Pygarrhichas, native to Central and South America.Definition from Wiktionary (CC BY-SA 3.0).EtymologyFrom tree + runner.nounA bird of the genera Margarornis or Pygarrhichas, native to Central and South America.Definitions & examples from Wiktionary (CC BY-SA 3.0).