Apennines Syllabification: (Ap·en·nines)Pronunciation: /ˈapəˌnīnz/Translate Apennines | into Italian Definition of Apennines a mountain range in Italy that extends for 880 miles (1,400 km) from the northwest to the southern tip of the country. Apennines in other Oxford dictionaries Definition of Apennines in the British & World English dictionary