Correct spelling for the English word "Arietation" is [ˌaɹa͡ɪ͡ətˈe͡ɪʃən], [ˌaɹaɪətˈeɪʃən], [ˌa_ɹ_aɪə_t_ˈeɪ_ʃ_ə_n] (IPA phonetic alphabet).
There doesn't appear to be any widely recognized term "Arietation" in the English language, and therefore, there is no available etymology for it. It's possible that it may be a misspelling or a rare term with limited usage.