Of uncertain origin; it was not in general use before the late 18th century. It may be a Latinate variant of the biblical name Adah. However, it has also been explained as a pet form of Adele and Adelaide, Germanic female names of which the first element is adal ‘noble’. It was borne by a 7th-century abbess of Saint-Julien-des-Prés at Le Mans.
Polish, Ukrainian, and Jewish (eastern Ashkenazic): regional name for someone from Podolia in Ukraine (Polish Podole, Yiddish podolye; a region which had a large Jewish population from the Middle Ages up to the Second World War), or a habitational name for someone from any of numerous other regions named Podole.