Guernsey1 Syllabification: (Guern·sey)Pronunciation: /ˈgərnzē/Translate Guernsey | into French | into Italian | into Spanish Definition of Guernsey an island in the English Channel, northwest of Jersey; population 65,900 (est. 2009); capital, St. Peter Port. Guernsey in other Oxford dictionaries Definition of Guernsey in the British & World English dictionary