tarmacadam Syllabification: (tar·mac·ad·am)Pronunciation: /ˈtärməˌkadəm/Definition of tarmacadam noun chiefly British another term for Tarmac.Derivatives tarmacadamed adjective Origin: late 19th century: from tar1 + macadamtarmacadam in other Oxford dictionaries Definition of tarmacadam in the British & World English dictionary