Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
aurīgātĭo, ōnis, f. [aurigo], a driving of a chariot in the course (very rare), Suet. Ner. 35.
Trop., of the dolphin: lusus, gestationes, aurigationes, Gell. 7, 8, 4.