Blavatsky, Helena Syllabification: (Bla·vat·sky, Helena)Pronunciation: /bləˈvatskē, -ˈvätskē/Definition of Blavatsky, Helena (1831–91), Russian spiritualist; born in Ukraine; born Helena Petrovna Hahn; known as Madame Blavatsky. In 1875, she cofounded the Theosophical Society in New York. Blavatsky, Helena in other Oxford dictionaries Definition of Blavatsky, Helena in the British & World English dictionary