The term 'Apple of ___' can be filled in with two different answers: PERU (4 letters) and FIONA (5 letters). The phrase 'Apple of ___' is an idiom that means someone or something that is greatly admired or cherished. In the case of PERU, it is a country located in South America that is known for its rich culture and history. FIONA is a female name of Scottish origin that means fair, white, and pure.