Sentence:  This leads Irenaeus to the somewhat startling <WSD>notion</WSD> that Adam and Eve died on the same day that they disobeyed , namely , on a Friday , as a parallel to the death of Christ on Good Friday ; he sees a parallel also to the Jewish day of preparation for the Sabbath . 
Meaning of the word marked with <WSD> tags:  a vague idea in which some confidence is placed