AD INFINITUM Meaning of AD INFINITUM in English ad infinitum BrE AmE ˌæd ˌɪn fɪ ˈnaɪt əm •ˌ•-, -fəˈ•- AmE \ -ˈnaɪt̬ əm ˌɑːd- Longman Pronunciation English Dictionary. Английский словарь произношений Longman. 2012