necropsy vs postmortem examination

necropsy and postmortem examination both are nouns.

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

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

necropsy 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 necropsy include autopsy, PM, post-mortem, post-mortem examination, postmortem.

necropsy (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