Entry 1 sense Webster, 1913 Oleandrin /ōl-ē-ăn'-drĭn/ · O·le·an·drin · IPA /oʊliːˈændrɪn/ 01 n. One of several cardiac glycosides (C32H48O9) found in oleander (Nerium oleander). 1. One of several cardiac glycosides (C32H48O9) found in oleander (Nerium oleander).(Chem.)