Home › Words › P › ptilochronologyptilochronologyptilochronology · noun — the study of feather growth rates as an index of nutritional condition in birds.Definition from Wiktionary (CC BY-SA 3.0).EtymologyFrom ptilo- + chronology; coined by Thomas C. Grubb, Jr.nounThe study of feather growth rates as an index of nutritional condition in birdsDefinitions & examples from Wiktionary (CC BY-SA 3.0).