The original idea was direct evidence from your own eyes.
Greek autós means self. In autopsía it combines with a seeing element to name seeing for oneself. English autopsy first had a broader direct-observation sense before its familiar medical specialization.
New Latin and earlier English observation uses are omitted from the slots. The source’s uncertain dating of early medical usage is not scored.
Sources
- Merriam-Webster: aut-
The combining form derives from Greek autós, self or the same.
- Merriam-Webster: autopsy
Word History gives Greek autopsía, the seeing formation, broader earlier English direct observation and the qualified history of the corpse-examination use.