γέρων/gérōn as a noun means “old man” in Ancient Greek, and just “old” as an adjective; I imagine the -to- part probably comes from the form γέροντος/gérontos (singular genitive) or γερόντων/geróntōn (plural genitive)
https://en.m.wiktionary.org/wiki/γέρων#Ancient_Greek
γέρων/gérōn as a noun means “old man” in Ancient Greek, and just “old” as an adjective; I imagine the -to- part probably comes from the form γέροντος/gérontos (singular genitive) or γερόντων/geróntōn (plural genitive) https://en.m.wiktionary.org/wiki/γέρων#Ancient_Greek