jack3 Syllabification: (jack)Pronunciation: /jak/Translate jack | into French | into German | into Italian | into Spanish Definition of jack verb [with object] informal take (something) illicitly; steal:his MO in the studio remains the same—jack other people’s tracks and present them in a new context rob (someone):they jacked him for his carOrigin: 1990s: from hijackjack in other Oxford dictionaries Definition of jack in the British & World English dictionary