extranet Syllabification: (ex·tra·net)Pronunciation: /ˈekstrəˌnet/Definition of extranet noun an intranet that can be partially accessed by authorized outside users, enabling businesses to exchange information over the Internet securely. Origin: 1990s: from extra- 'outside' + net, by analogy with intranetextranet in other Oxford dictionaries Definition of extranet in the British & World English dictionary