Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† aeōn, ōnis, m., = αἰών (age, eternity). Often used by Tert. adv. Haer. 33; 34; 49, and adv. Valentin., who invented much concerning the Thirty Æons, whom he maintained to be gods.