autopsy vs postmortem examination

autopsy and postmortem examination both are nouns.

Word	Noun	Adjective	Verb	Adverb
autopsy	Yes	No	Yes	No
postmortem examination	Yes	No	No	No

As nouns, autopsy and postmortem examination are synonyms defined as:

autopsy and postmortem examination: an examination and dissection of a dead body to determine cause of death or the changes produced by disease

Other synonyms of autopsy include necropsy, PM, post-mortem, post-mortem examination, postmortem.

autopsy (noun)	postmortem examination (noun)
an examination and dissection of a dead body to determine cause of death or the changes produced by disease	an examination and dissection of a dead body to determine cause of death or the changes produced by disease

autopsy (verb)	postmortem examination (verb)
perform an autopsy on a dead body; do a post-mortem