ブラウザの設定でJava Scriptの使用を有効にしてご利用ください。
出典:Wiktionary
By rebracketing of words formed from first conjugation verbs, such as accūsātiō (accūsāre + -tiō), where -ā- is part of the stem.
-ātiō f
Third-declension noun.
-atio