Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Parthāon, ŏnis, m., = Παρθάων, son of Agenor and Epicaste, king of Calydon, and father of Œneus: ego te simitu novi cum Parthaone, I know you as well as I do Parthaon, i. e. not at all, Plaut. Men. 5, 1, 45: Parthaone nate, i. e. Œneus, Ov. M. 9, 12; cf. Hyg. Fab. 175; 239 and 242.
Hence,