Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
rĕgĕnĕrātĭo, ōnis, f. [regenero], a being born again, regeneration (eccl. Lat.), Aug. Civ. Dei, 20, 5; Vulg. Matt. 19, 28; id. Tit. 3, 5: lavacrum regenerationis, of baptism, Aug. Civ. Dei, 22, 8, 5.